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UQO Working Paper No. 10 — The assessment gap in Quebec: vertical and horizontal inequity in municipal property assessment.

WP10 — The Assessment Gap in Quebec: full research project

End-to-end pipeline (sample, IAAO diagnostics, Cheng FE / Clapp IV /
quantile / heterogeneity / horizontal / tax shift), 10 journal-calibre
figures, 10 LaTeX tables, 29-page paper with literature review.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Simon-Pierre Boucher committed (Aug 9, 2026) Browse files

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1 +# Raw data snapshot — 100 MB parquet, not redistributed
2 +data/raw/*.parquet
3 +data/processed/*.parquet
4 +
5 +# Python
6 +__pycache__/
7 +*.pyc
8 +
9 +# LaTeX build artifacts (paper/main.pdf IS committed)
10 +paper/*.aux
11 +paper/*.log
12 +paper/*.out
13 +paper/*.fls
14 +paper/*.fdb_latexmk
15 +paper/*.bbl
16 +paper/*.blg
17 +paper/*.synctex.gz
18 +
19 +# macOS
20 +.DS_Store
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1 +<!-- Author: Simon-Pierre Boucher — contact@spboucher.ai -->
2 +# ⚖️ The Assessment Gap in Quebec
3 +
4 +**UQO Working Paper No. 10** — *Vertical and Horizontal Inequity in Municipal
5 +Property Valuation: Evidence from 522,769 Sales Matched to the Assessment Roll*
6 +
7 +[![Paper](https://img.shields.io/badge/paper-PDF%20(29%20p.)-b31b1b?logo=latex&logoColor=white)](paper/main.pdf)
8 +[![Python](https://img.shields.io/badge/python-3.11%2B-3776AB?logo=python&logoColor=white)](requirements.txt)
9 +[![Data](https://img.shields.io/badge/data-745%2C119%20matched%20sales%20·%20parquet-4051b5)](data/raw/README.md)
10 +[![Estimation](https://img.shields.io/badge/estimation-statsmodels%20·%20linearmodels%20(AbsorbingLS%20%2B%20IV2SLS)-4051b5)](src/wp10/models.py)
11 +[![Reproducible](https://img.shields.io/badge/reproducible-end--to--end%20pipeline-2e7d32)](scripts/)
12 +[![Institution](https://img.shields.io/badge/UQO-D%C3%A9pt.%20des%20sciences%20administratives-16365c)](https://uqo.ca)
13 +[![Author](https://img.shields.io/badge/author-Simon--Pierre%20Boucher-16365c)](mailto:contact@spboucher.ai)
14 +[![Contact](https://img.shields.io/badge/contact-contact%40spboucher.ai-a02020?logo=maildotru&logoColor=white)](mailto:contact@spboucher.ai)
15 +
16 +> **TL;DR** — Matching 522,769 Quebec residential sales (2021–2026) to the triennial
17 +> assessment rolls that tax them, this paper delivers the **first province-wide audit
18 +> of property-assessment equity in Canada**. Within the same municipality × roll ×
19 +> year, the elasticity of the assessment ratio w.r.t. price is **−0.34** (Cheng FE)
20 +> and still **−0.08** under Clapp's measurement-error-robust IV. **99% of
21 +> municipalities** fail the IAAO uniformity standard, **95%** fail its vertical-equity
22 +> standard — Montréal is the lone progressive large market. The median dwelling in the
23 +> bottom local price decile pays **~65% more property tax** than uniform assessment
24 +> would imply; the top decile pays ~5% less.
25 +
26 +---
27 +
28 +## 📖 Table of contents
29 +
30 +1. [What this paper does](#-what-this-paper-does)
31 +2. [Headline results](#-headline-results)
32 +3. [Repository layout](#-repository-layout)
33 +4. [Quick start](#-quick-start)
34 +5. [The pipeline, step by step](#-the-pipeline-step-by-step)
35 +6. [Data](#-data)
36 +7. [Methodology](#-methodology)
37 +8. [Figures & tables inventory](#-figures--tables-inventory)
38 +9. [Limitations](#-limitations)
39 +10. [Citation](#-citation)
40 +11. [Author & contact](#-author--contact)
41 +
42 +---
43 +
44 +## 🎯 What this paper does
45 +
46 +Quebec taxes every dwelling in proportion to its **assessed value**, redrawn on a
47 +triennial roll whose values must, by statute (art. 46 LFM), reflect market conditions
48 +at a single reference date. If assessments are *regressive* — cheap homes overvalued
49 +relative to expensive ones — the effective tax rate falls with wealth, silently.
50 +This project measures that gap at province scale:
51 +
52 +```
53 +ln AV_i = α_c(i) + β · ln SP_i + ε_i (c = municipality × roll × sale-year)
54 +```
55 +
56 +- **γ = β − 1** is the elasticity of the assessment ratio w.r.t. price
57 + (γ < 0 ⇒ regressive), identified **within** 2,884 market-timing cells;
58 +- the **Clapp (1990) rank IV** purges the attenuation bias that pushes naïve
59 + ratio studies toward spurious regressivity;
60 +- the full **IAAO ratio-study battery** (median ratio, COD, PRD, PRB) with
61 + bootstrap CIs is computed for every municipality with ≥ 100 usable sales;
62 +- quantile profiles, subgroup elasticities, horizontal-dispersion regressions and
63 + an exact **intra-municipal tax-shift** calculation complete the audit.
64 +
65 +## 🏆 Headline results
66 +
67 +| Object | Estimate |
68 +|---|---|
69 +| Cheng elasticity, pooled OLS | β = 0.812 (0.029) |
70 +| Cheng elasticity, cell FE | **β = 0.656 (0.029)** → γ = −0.344 |
71 +| Clapp rank-IV (error-robust) | **β = 0.917 (0.021)** → γ = −0.083 |
72 +| Quantile profile β(τ), τ = .10 → .90 | 0.87 → **0.49** (failure concentrated at the top) |
73 +| Province-wide PRB (2021 / 2024) | −0.104 / −0.002 (staleness mechanism) |
74 +| Municipalities with PRB < 0 | **99%** (95% below IAAO band) |
75 +| Median municipality COD | 26 (IAAO ceiling: 15) |
76 +| Excess tax, bottom ↔ top local decile | **+65% ↔ −5%** (median) |
77 +| The exception | Montréal: PRB **+0.07**, progressive in all 6 years |
78 +
79 +Sub-group anatomy: condos γ = −0.12 vs single-family −0.45 / plex −0.49;
80 +land share > 0.4 → −0.50; age > 60 y → −0.43; large markets (>10k sales) −0.27.
81 +
82 +## 🗂 Repository layout
83 +
84 +```
85 +wp10_uqo/
86 +├── data/
87 +│ ├── raw/ # matched sales–roll snapshot (see data/raw/README.md)
88 +│ └── processed/ # analysis.parquet (built by step 01)
89 +├── src/wp10/ # reusable package
90 +│ ├── config.py # paths, thresholds, constants
91 +│ ├── sample.py # sample construction & variable definitions
92 +│ ├── iaao.py # COD / PRD / PRB + bootstrap CIs
93 +│ ├── models.py # Cheng FE, Clapp IV, quantiles, horizontal, tax shift
94 +│ └── plotstyle.py # journal-calibre matplotlib style (validated palette)
95 +├── scripts/ # the pipeline, in order
96 +│ ├── 01_build_sample.py
97 +│ ├── 02_iaao_stats.py
98 +│ ├── 03_estimate_regressions.py
99 +│ ├── 04_make_figures.py
100 +│ └── 05_make_tables.py
101 +├── results/
102 +│ ├── reproduced/ # every CSV the scripts emit
103 +│ └── tables/ # LaTeX tables input by the paper
104 +├── figures/ # 10 publication figures (PNG, 300 dpi)
105 +└── paper/ # main.tex + sections/ + references.bib → main.pdf
106 +```
107 +
108 +## 🚀 Quick start
109 +
110 +```bash
111 +cd wp10_uqo
112 +python3 -m pip install -r requirements.txt
113 +
114 +# place the parquet snapshot in data/raw/ (see data/raw/README.md), then:
115 +python3 scripts/01_build_sample.py # 745,119 → 522,769 sales
116 +python3 scripts/02_iaao_stats.py # IAAO diagnostics + bootstrap
117 +python3 scripts/03_estimate_regressions.py # FE / IV / quantile / heterogeneity / tax shift
118 +python3 scripts/04_make_figures.py # 10 figures
119 +python3 scripts/05_make_tables.py # 10 LaTeX tables
120 +
121 +cd paper && make # compile main.pdf (latexmk)
122 +```
123 +
124 +Total runtime ≈ 5 minutes on an Apple-silicon laptop; peak RAM ≈ 6 GB.
125 +
126 +## 🗃 Data
127 +
128 +745,119 residential-market transactions (Jan 2021 – Jul 2026) matched at the
129 +**parcel level** to the assessment roll in force at the sale date (median match
130 +distance 0.6 m; every retained sale reproduces the roll value exactly). From the
131 +roll: total/land/building assessed values, lot & floor areas, year built, unit
132 +count, CUBF use code, roll vintage and the statutory market-condition date.
133 +Sample cascade (details in the paper, §4): residential CUBF → match quality →
134 +valid AV/SP → 1/99% ratio trim within roll vintage → cells ≥ 20 sales
135 +⇒ **522,769 sales, 625 municipalities, 2,884 cells**.
136 +
137 +## 🔬 Methodology
138 +
139 +1. **IAAO diagnostics** (Standard on Ratio Studies, 2013) within
140 + municipality × sale-year blocks, aggregated by median — COD, PRD, PRB with
141 + percentile-bootstrap CIs (`src/wp10/iaao.py`).
142 +2. **Cheng (1974) log-log regression** with 2,884 absorbed fixed effects
143 + (linearmodels `AbsorbingLS`), SEs clustered on 625 municipalities.
144 +3. **Clapp (1990) rank IV** — Z ∈ {−1,0,+1} from within-cell rank agreement of
145 + ln AV and ln SP, 2SLS on demeaned data (`IV2SLS`) — the conservative bound.
146 +4. **Quantile regressions** on within-cell demeaned data (τ = .10….90).
147 +5. **Heterogeneity**: separate FE estimates by class, age, land share, roll lag,
148 + municipality size, sale year.
149 +6. **Horizontal inequity**: |ln r − cell median| regressed on characteristics.
150 +7. **Tax shift**: r / cell-median − 1 by within-cell price decile — exact %
151 + over/under-payment under Quebec's exemption-free ad valorem rule.
152 +
153 +## 🖼 Figures & tables inventory
154 +
155 +| Figure | Content |
156 +|---|---|
157 +| `fig_ratio_dist` | ratio distribution + by roll lag (Panels A/B) |
158 +| `fig_time` | median ratio by month × roll vintage (staleness drift) |
159 +| `fig_binscatter` | within-cell ln ratio vs ln price, 20 bins — the core fact |
160 +| `fig_quantile` | β(τ) profile with FE/IV benchmarks |
161 +| `fig_heterogeneity` | forest plot of subgroup γ |
162 +| `fig_prb_muni`, `fig_cod` | municipal PRB / COD distributions vs IAAO bands |
163 +| `fig_map` | province map of municipal PRB (Montréal exception) |
164 +| `fig_taxshift` | excess tax burden by local price decile |
165 +| `fig_robustness` | γ_FE vs γ_IV across 10 sample variants |
166 +
167 +Tables (`results/tables/*.tex`): summary stats, IAAO province-wide, ten largest
168 +markets, vertical regressions, quantiles, heterogeneity, horizontal, tax shift,
169 +robustness, Paglin–Fogarty.
170 +
171 +## ⚠️ Limitations
172 +
173 +- Sales < $50k absent from the source registry; residual non-arm's-length
174 + transfers may survive screens (bottom-decile shift = upper bound).
175 +- 2021–2026 is an unusually turbulent market — levels statistics are
176 + period-specific (the within-market elasticity is not).
177 +- No appeals, renovations, or owner demographics observed.
178 +- Montréal's progressivity may partly reflect borough-level composition.
179 +
180 +## 📝 Citation
181 +
182 +```bibtex
183 +@techreport{boucher2026assessmentgap,
184 + author = {Boucher, Simon-Pierre},
185 + title = {The Assessment Gap in Quebec: Vertical and Horizontal Inequity
186 + in Municipal Property Valuation},
187 + institution = {Universit\'e du Qu\'ebec en Outaouais,
188 + D\'epartement des sciences administratives},
189 + type = {Working Paper},
190 + number = {10},
191 + year = {2026},
192 + month = {August}
193 +}
194 +```
195 +
196 +## 👤 Author & contact
197 +
198 +**Simon-Pierre Boucher** — Département des sciences administratives,
199 +Université du Québec en Outaouais (UQO), Gatineau, QC.
200 +📧 [contact@spboucher.ai](mailto:contact@spboucher.ai)
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1 +<!-- Author: Simon-Pierre Boucher — contact@spboucher.ai -->
2 +# Raw data
3 +
4 +`transactions_700k_avec_registre_foncier.parquet` — 745,119 Quebec
5 +residential-market transactions (January 2021 – July 2026) matched at the
6 +parcel level to the municipal assessment roll (rôle d'évaluation foncière)
7 +in force at the sale date.
8 +
9 +| Group | Key columns |
10 +|---|---|
11 +| Transaction | `id`, `date`, `amount`, `street`, `zipCode`, `city`, `lat`, `lng`, `propertyType`, `ownerType`, `tx_year` |
12 +| Roll identity | `role_id_provinc`, `role_matricule`, `role_code_mun`, `role_municipalite`, `role_anrole` (roll vintage), `role_date_cond_marche` (statutory market-condition reference date) |
13 +| Roll values | `role_valeur_immeuble` (total AV), `role_valeur_terrain` (land), `role_valeur_batiment` (building), `role_valeur_role_anterieur`, `previousValue`, `totalArValue` |
14 +| Roll structure | `role_cubf` (+ `role_cubf_libelle`), `role_superficie_terrain_m2`, `role_aire_etages_m2`, `role_annee_construction`, `role_nb_logements`, `role_nb_etages`, `role_lien_physique`, `role_genre_construction`, `role_unite_voisinage` |
15 +| Match quality | `match_dist_m` (median 0.6 m), `match_score` (max 220), `match_valeur_exacte` |
16 +
17 +The file is **not redistributed** with the repository (100 MB; see
18 +`.gitignore`). Place it in this directory before running the pipeline.
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1 +# Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +$pdf_mode = 1;
3 +$pdflatex = 'pdflatex -interaction=nonstopmode -halt-on-error -synctex=1 %O %S';
4 +$bibtex_use = 2;
5 +$clean_ext = 'synctex.gz run.xml bbl bcf fdb_latexmk fls log aux out toc lof lot blg';
6 +@default_files = ('main.tex');
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1 +# Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +all:
3 + latexmk -pdf main.tex
4 +
5 +clean:
6 + latexmk -c
7 +
8 +distclean:
9 + latexmk -C
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1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +% UQO Working Paper No. 10
4 +% The Assessment Gap in Quebec: Vertical and Horizontal Inequity in
5 +% Municipal Property Valuation
6 +%
7 +% Build: latexmk -pdf main.tex (or `make` in this directory)
8 +% Figures are read from ../figures/, tables from ../results/tables/.
9 +% ============================================================================
10 +\documentclass[12pt,letterpaper]{article}
11 +
12 +% ---------------------------------------------------------------- encoding
13 +\usepackage[utf8]{inputenc}
14 +\usepackage[T1]{fontenc}
15 +\usepackage[english]{babel}
16 +
17 +% ---------------------------------------------------------------- layout
18 +\usepackage[letterpaper,margin=1in]{geometry}
19 +\usepackage{setspace}
20 +\onehalfspacing
21 +
22 +% ---------------------------------------------------------------- typography
23 +\usepackage{mathptmx}
24 +\usepackage{microtype}
25 +
26 +% ---------------------------------------------------------------- math
27 +\usepackage{amsmath,amssymb,amsthm}
28 +
29 +% ---------------------------------------------------------------- tables
30 +\usepackage{booktabs}
31 +\usepackage{threeparttable}
32 +\usepackage{makecell}
33 +
34 +% ---------------------------------------------------------------- figures
35 +\usepackage{graphicx}
36 +\usepackage{subcaption}
37 +\graphicspath{{../figures/}{./}}
38 +
39 +% ---------------------------------------------------------------- captions
40 +\usepackage[font=small,labelfont=bf,labelsep=period,justification=justified,singlelinecheck=false]{caption}
41 +
42 +% ---------------------------------------------------------------- colours & links
43 +\usepackage[dvipsnames]{xcolor}
44 +\usepackage[colorlinks=true,linkcolor=NavyBlue,citecolor=NavyBlue,urlcolor=NavyBlue,breaklinks=true]{hyperref}
45 +
46 +% ---------------------------------------------------------------- bibliography
47 +\usepackage[authoryear,round,semicolon]{natbib}
48 +\bibliographystyle{aer}
49 +
50 +% ---------------------------------------------------------------- headings & lists
51 +\usepackage{titlesec}
52 +\titleformat{\section}{\large\bfseries}{\thesection.}{0.5em}{}
53 +\titleformat{\subsection}{\normalsize\bfseries}{\thesubsection.}{0.5em}{}
54 +\titleformat{\subsubsection}{\normalsize\itshape}{\thesubsubsection.}{0.5em}{}
55 +\usepackage{fancyhdr}
56 +\pagestyle{fancy}\fancyhf{}
57 +\renewcommand{\headrulewidth}{0pt}
58 +\fancyfoot[C]{\thepage}
59 +\usepackage{enumitem}
60 +\setlist{nosep,leftmargin=*}
61 +
62 +% ============================================================================
63 +% METADATA
64 +% ============================================================================
65 +\newcommand{\WPnumber}{10}
66 +\newcommand{\WPtitle}{The Assessment Gap in Quebec}
67 +\newcommand{\WPsubtitle}{Vertical and Horizontal Inequity in Municipal Property
68 + Valuation: Evidence from 522{,}769 Sales Matched to the Assessment Roll}
69 +\newcommand{\WPdate}{August 2026}
70 +\newcommand{\WPversion}{1.0}
71 +\newcommand{\WPkeywords}{Property tax, Assessment, Vertical equity,
72 + Regressivity, Ratio study, Quebec}
73 +\newcommand{\WPjel}{H71, H22, R51, R31}
74 +
75 +\newcommand{\WPauthor}{Simon-Pierre Boucher}
76 +\newcommand{\WPaffiliation}{D\'epartement des sciences administratives\\
77 + Universit\'e du Qu\'ebec en Outaouais}
78 +\newcommand{\WPemail}{simon-pierre.boucher@uqo.ca}
79 +\newcommand{\WPaddress}{Gatineau -- Pavillon Alexandre-Tach\'e\\
80 + 283, boulevard Alexandre-Tach\'e\\ Gatineau, Qu\'ebec, Canada J9A 1L8}
81 +
82 +\newcommand{\WPabstract}{%
83 +Municipal property taxes are levied on assessed values, so any systematic
84 +relationship between assessment accuracy and market value silently
85 +redistributes the tax burden. Matching 522{,}769 residential transactions
86 +from 2021--2026 to the triennial assessment rolls of 625 Quebec
87 +municipalities at the parcel level, we provide the first province-wide
88 +evaluation of vertical and horizontal equity in Canadian property assessment.
89 +Assessment ratios decline steeply with price: within
90 +municipality~$\times$~roll~$\times$~sale-year markets, the elasticity of the
91 +assessment ratio with respect to the sale price is $-0.34$, and a rank-based
92 +instrumental-variable estimator in the spirit of \mbox{Clapp (1990)}---which
93 +purges the attenuation bias that pushes least-squares tests toward spurious
94 +regressivity---still yields $-0.08$ ($t\approx4$). IAAO ratio-study
95 +diagnostics place 95\% of municipalities below the acceptable price-related
96 +bias band and 99\% above the COD uniformity ceiling; Montr\'eal is the only
97 +large market whose assessments are progressive. Regressivity is strongest for
98 +single-family homes, older buildings, properties with a high assessed land
99 +share, and smaller municipalities, and it doubles in years when market prices
100 +decouple from the rolls' reference dates, pointing to infrequent revaluation
101 +as a first-order mechanism. The implied intra-municipal tax shift is large:
102 +the median dwelling in the bottom within-market price decile pays roughly
103 +65\% more property tax than it would under uniform assessment, while the top
104 +decile pays about 5\% less.}
105 +
106 +\begin{document}
107 +
108 +\input{sections/titlepage}
109 +
110 +\setcounter{page}{1}
111 +\input{sections/introduction}
112 +\input{sections/literature}
113 +\input{sections/institutional}
114 +\input{sections/data}
115 +\input{sections/methodology}
116 +\input{sections/results}
117 +\input{sections/robustness}
118 +\input{sections/discussion}
119 +\input{sections/conclusion}
120 +
121 +\newpage
122 +\bibliography{references}
123 +
124 +\end{document}
added paper/references.bib +402 −0
@@ -0,0 +1,402 @@
1 +@comment{ Author: Simon-Pierre Boucher (contact at spboucher.ai) -- Bibliography for UQO Working Paper No 10 }
2 +
3 +@article{paglin1972equity,
4 + author = {Paglin, Morton and Fogarty, Michael},
5 + title = {Equity and the Property Tax: A New Conceptual Focus},
6 + journal = {National Tax Journal},
7 + year = {1972},
8 + volume = {25},
9 + number = {4},
10 + pages = {557--565}
11 +}
12 +
13 +@article{cheng1974property,
14 + author = {Cheng, Pao Lun},
15 + title = {Property Taxation, Assessment Performance, and Its Measurement},
16 + journal = {Public Finance},
17 + year = {1974},
18 + volume = {29},
19 + number = {3},
20 + pages = {268--284}
21 +}
22 +
23 +@article{kochin1982vertical,
24 + author = {Kochin, Levis A. and Parks, Richard W.},
25 + title = {Vertical Equity in Real Estate Assessment: A Fair Appraisal},
26 + journal = {Economic Inquiry},
27 + year = {1982},
28 + volume = {20},
29 + number = {4},
30 + pages = {511--532}
31 +}
32 +
33 +@article{bell1984administrative,
34 + author = {Bell, Earl J.},
35 + title = {Administrative Inequity and Property Assessment: The Case for the Traditional Approach},
36 + journal = {Property Tax Journal},
37 + year = {1984},
38 + volume = {3},
39 + number = {2},
40 + pages = {123--131}
41 +}
42 +
43 +@article{kennedy1984unfair,
44 + author = {Kennedy, Peter},
45 + title = {On an Unfair Appraisal of Vertical Equity in Real Estate Assessment},
46 + journal = {Economic Inquiry},
47 + year = {1984},
48 + volume = {22},
49 + number = {2},
50 + pages = {287--290}
51 +}
52 +
53 +@article{sunderman1990testing,
54 + author = {Sunderman, Mark A. and Birch, John W. and Cannaday, Roger E. and Hamilton, Thomas W.},
55 + title = {Testing for Vertical Inequity in Property Tax Systems},
56 + journal = {Journal of Real Estate Research},
57 + year = {1990},
58 + volume = {5},
59 + number = {3},
60 + pages = {319--334}
61 +}
62 +
63 +@article{clapp1990new,
64 + author = {Clapp, John M.},
65 + title = {A New Test for Equitable Real Estate Tax Assessment},
66 + journal = {Journal of Real Estate Finance and Economics},
67 + year = {1990},
68 + volume = {3},
69 + number = {3},
70 + pages = {233--249}
71 +}
72 +
73 +@article{sirmans1995vertical,
74 + author = {Sirmans, G. Stacy and Diskin, Barry A. and Friday, H. Swint},
75 + title = {Vertical Inequity in the Taxation of Real Property},
76 + journal = {National Tax Journal},
77 + year = {1995},
78 + volume = {48},
79 + number = {1},
80 + pages = {71--84}
81 +}
82 +
83 +@article{allen2002measuring,
84 + author = {Allen, Marcus T. and Dare, William H.},
85 + title = {Identifying Determinants of Horizontal Property Tax Inequity: Evidence from Florida},
86 + journal = {Journal of Real Estate Research},
87 + year = {2002},
88 + volume = {24},
89 + number = {2},
90 + pages = {153--164}
91 +}
92 +
93 +@article{sirmans2008vertical,
94 + author = {Sirmans, G. Stacy and Gatzlaff, Dean H. and Macpherson, David A.},
95 + title = {Horizontal and Vertical Inequity in Real Property Taxation},
96 + journal = {Journal of Real Estate Literature},
97 + year = {2008},
98 + volume = {16},
99 + number = {2},
100 + pages = {167--180}
101 +}
102 +
103 +@article{mcmillen2008thin,
104 + author = {McMillen, Daniel P. and Weber, Rachel N.},
105 + title = {Thin Markets and Property Tax Inequities: A Multinomial Logit Approach},
106 + journal = {National Tax Journal},
107 + year = {2008},
108 + volume = {61},
109 + number = {4},
110 + pages = {653--671}
111 +}
112 +
113 +@article{mcmillen2011assessment,
114 + author = {McMillen, Daniel P.},
115 + title = {Assessment Regressivity: A Tale of Two {Illinois} Counties},
116 + journal = {Land Lines},
117 + year = {2011},
118 + volume = {23},
119 + number = {1},
120 + pages = {9--15}
121 +}
122 +
123 +@article{hodge2017assessment,
124 + author = {Hodge, Timothy R. and McMillen, Daniel P. and Sands, Gary and Skidmore, Mark},
125 + title = {Assessment Inequity in a Declining Housing Market: The Case of {Detroit}},
126 + journal = {Real Estate Economics},
127 + year = {2017},
128 + volume = {45},
129 + number = {2},
130 + pages = {237--258}
131 +}
132 +
133 +@article{mcmillen2020assessment,
134 + author = {McMillen, Daniel and Singh, Ruchi},
135 + title = {Assessment Regressivity and Property Taxation},
136 + journal = {Journal of Real Estate Finance and Economics},
137 + year = {2020},
138 + volume = {60},
139 + number = {1},
140 + pages = {155--169}
141 +}
142 +
143 +@article{avenancio2022assessment,
144 + author = {Avenancio-Le{\'o}n, Carlos F. and Howard, Troup},
145 + title = {The Assessment Gap: Racial Inequalities in Property Taxation},
146 + journal = {Quarterly Journal of Economics},
147 + year = {2022},
148 + volume = {137},
149 + number = {3},
150 + pages = {1383--1434}
151 +}
152 +
153 +@techreport{berry2021reassessing,
154 + author = {Berry, Christopher R.},
155 + title = {Reassessing the Property Tax},
156 + institution = {University of Chicago, Harris School of Public Policy},
157 + type = {Working Paper},
158 + year = {2021}
159 +}
160 +
161 +@techreport{amornsiripanitch2022residential,
162 + author = {Amornsiripanitch, Natee},
163 + title = {Why Are Residential Property Tax Rates Regressive?},
164 + institution = {Federal Reserve Bank of Philadelphia},
165 + type = {Working Paper},
166 + number = {22-02},
167 + year = {2022}
168 +}
169 +
170 +@article{mcmillen2022allocative,
171 + author = {McMillen, Daniel and Singh, Ruchi},
172 + title = {Measures of Vertical Inequality in Assessments},
173 + journal = {Journal of Real Estate Finance and Economics},
174 + year = {2022},
175 + volume = {online first},
176 + pages = {1--29}
177 +}
178 +
179 +@book{iaao2013standard,
180 + author = {{International Association of Assessing Officers}},
181 + title = {Standard on Ratio Studies},
182 + publisher = {IAAO},
183 + address = {Kansas City, MO},
184 + year = {2013}
185 +}
186 +
187 +@book{eckert1990property,
188 + author = {Eckert, Joseph K. and Gloudemans, Robert J. and Almy, Richard R.},
189 + title = {Property Appraisal and Assessment Administration},
190 + publisher = {International Association of Assessing Officers},
191 + address = {Chicago},
192 + year = {1990}
193 +}
194 +
195 +@book{gloudemans2011fundamentals,
196 + author = {Gloudemans, Robert and Almy, Richard},
197 + title = {Fundamentals of Mass Appraisal},
198 + publisher = {International Association of Assessing Officers},
199 + address = {Kansas City, MO},
200 + year = {2011}
201 +}
202 +
203 +@article{oates1969effects,
204 + author = {Oates, Wallace E.},
205 + title = {The Effects of Property Taxes and Local Public Spending on Property Values: An Empirical Study of Tax Capitalization and the {Tiebout} Hypothesis},
206 + journal = {Journal of Political Economy},
207 + year = {1969},
208 + volume = {77},
209 + number = {6},
210 + pages = {957--971}
211 +}
212 +
213 +@article{oates2016local,
214 + author = {Oates, Wallace E. and Fischel, William A.},
215 + title = {Are Local Property Taxes Regressive, Progressive, or What?},
216 + journal = {National Tax Journal},
217 + year = {2016},
218 + volume = {69},
219 + number = {2},
220 + pages = {415--434}
221 +}
222 +
223 +@article{rosen1974hedonic,
224 + author = {Rosen, Sherwin},
225 + title = {Hedonic Prices and Implicit Markets: Product Differentiation in Pure Competition},
226 + journal = {Journal of Political Economy},
227 + year = {1974},
228 + volume = {82},
229 + number = {1},
230 + pages = {34--55}
231 +}
232 +
233 +@incollection{malpezzi2003hedonic,
234 + author = {Malpezzi, Stephen},
235 + title = {Hedonic Pricing Models: A Selective and Applied Review},
236 + booktitle = {Housing Economics and Public Policy},
237 + editor = {O'Sullivan, Tony and Gibb, Kenneth},
238 + publisher = {Blackwell},
239 + address = {Oxford},
240 + year = {2003},
241 + pages = {67--89}
242 +}
243 +
244 +@article{carbonnier2024property,
245 + author = {Carbonnier, Cl{\'e}ment},
246 + title = {Property Tax Regressivity, the Case of {Qu{\'e}bec}},
247 + journal = {Public Finance Review},
248 + year = {2024},
249 + volume = {52},
250 + number = {2},
251 + pages = {155--181}
252 +}
253 +
254 +@techreport{slack2014political,
255 + author = {Slack, Enid and Bird, Richard M.},
256 + title = {The Political Economy of Property Tax Reform},
257 + institution = {OECD},
258 + type = {OECD Working Papers on Fiscal Federalism},
259 + number = {18},
260 + year = {2014}
261 +}
262 +
263 +@book{youngman2016good,
264 + author = {Youngman, Joan},
265 + title = {A Good Tax: Legal and Policy Issues for the Property Tax in the {United States}},
266 + publisher = {Lincoln Institute of Land Policy},
267 + address = {Cambridge, MA},
268 + year = {2016}
269 +}
270 +
271 +@techreport{found2017property,
272 + author = {Found, Adam and Tomlinson, Peter},
273 + title = {Business Tax Burdens in {Canada's} Major Cities: The 2017 Report Card},
274 + institution = {C.D. Howe Institute},
275 + type = {E-Brief},
276 + year = {2017}
277 +}
278 +
279 +@techreport{mpac2022vertical,
280 + author = {{Municipal Property Assessment Corporation}},
281 + title = {Vertical Equity Review of Residential Assessed Values},
282 + institution = {MPAC},
283 + address = {Toronto},
284 + type = {Technical Report},
285 + year = {2022}
286 +}
287 +
288 +@article{goolsby1997assessment,
289 + author = {Goolsby, William C.},
290 + title = {Assessment Error in the Valuation of Owner-Occupied Housing},
291 + journal = {Journal of Real Estate Research},
292 + year = {1997},
293 + volume = {13},
294 + number = {1},
295 + pages = {33--45}
296 +}
297 +
298 +@article{quintos2020prb,
299 + author = {Quintos, Carmela},
300 + title = {A Gradient Boosting Approach to Understanding Vertical and Horizontal Inequity in Property Assessments},
301 + journal = {Journal of Property Tax Assessment \& Administration},
302 + year = {2020},
303 + volume = {17},
304 + number = {2},
305 + pages = {1--28}
306 +}
307 +
308 +@article{ross2012assessor,
309 + author = {Ross, Justin M.},
310 + title = {Interjurisdictional Determinants of Property Assessment Regressivity},
311 + journal = {Land Economics},
312 + year = {2012},
313 + volume = {88},
314 + number = {1},
315 + pages = {28--42}
316 +}
317 +
318 +@article{plummer2014evidence,
319 + author = {Plummer, Elizabeth},
320 + title = {The Effects of Property Tax Protests on the Assessment Uniformity of Residential Properties},
321 + journal = {Real Estate Economics},
322 + year = {2014},
323 + volume = {42},
324 + number = {4},
325 + pages = {900--937}
326 +}
327 +
328 +@article{clapp1990methods,
329 + author = {Clapp, John M.},
330 + title = {A Methodology for Constructing Vacant Land Price Indices},
331 + journal = {Real Estate Economics},
332 + year = {1990},
333 + volume = {18},
334 + number = {3},
335 + pages = {274--293}
336 +}
337 +
338 +@misc{lfm2026,
339 + author = {{Gouvernement du Qu\'ebec}},
340 + title = {Loi sur la fiscalit\'e municipale, {RLRQ}, c.\ {F-2.1}},
341 + howpublished = {L\'egisQu\'ebec},
342 + year = {2026},
343 + note = {Articles 42--46 (triennial rolls and market-condition reference date)}
344 +}
345 +
346 +@misc{mamh2024manuel,
347 + author = {{Minist\`ere des Affaires municipales et de l'Habitation}},
348 + title = {Manuel d'\'evaluation fonci\`ere du {Qu\'ebec}},
349 + howpublished = {Gouvernement du Qu\'ebec},
350 + address = {Qu\'ebec},
351 + year = {2024}
352 +}
353 +
354 +@article{desrosiers2000hedonic,
355 + author = {Des Rosiers, Fran{\c c}ois and Th{\'e}riault, Marius and Villeneuve, Paul-Y.},
356 + title = {Sorting Out Access and Neighbourhood Factors in Hedonic Price Modelling},
357 + journal = {Journal of Property Investment \& Finance},
358 + year = {2000},
359 + volume = {18},
360 + number = {3},
361 + pages = {291--315}
362 +}
363 +
364 +@article{bostic2007land,
365 + author = {Bostic, Raphael W. and Longhofer, Stanley D. and Redfearn, Christian L.},
366 + title = {Land Leverage: Decomposing Home Price Dynamics},
367 + journal = {Real Estate Economics},
368 + year = {2007},
369 + volume = {35},
370 + number = {2},
371 + pages = {183--208}
372 +}
373 +
374 +@article{ihlanfeldt2023appraisal,
375 + author = {Ihlanfeldt, Keith and Rodgers, Luke P.},
376 + title = {Homestead Exemptions, Heterogeneous Assessment, and Property Tax Progressivity},
377 + journal = {National Tax Journal},
378 + year = {2022},
379 + volume = {75},
380 + number = {1},
381 + pages = {7--31}
382 +}
383 +
384 +@article{baar1981property,
385 + author = {Baar, Kenneth K.},
386 + title = {Property Tax Assessment Discrimination Against Low-Income Neighborhoods},
387 + journal = {The Urban Lawyer},
388 + year = {1981},
389 + volume = {13},
390 + number = {3},
391 + pages = {333--406}
392 +}
393 +
394 +@article{engle1975deassessment,
395 + author = {Engle, Robert F.},
396 + title = {De Facto Discrimination in Residential Assessments: {Boston}},
397 + journal = {National Tax Journal},
398 + year = {1975},
399 + volume = {28},
400 + number = {4},
401 + pages = {445--451}
402 +}
added paper/sections/conclusion.tex +37 −0
@@ -0,0 +1,37 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Conclusion}
4 +\label{sec:concl}
5 +
6 +Matching more than half a million residential sales to the assessment
7 +rolls that tax them, this paper delivers the first province-wide audit of
8 +assessment equity in Canada. The verdict is unambiguous. Quebec's
9 +property-tax base is systematically regressive: within the same
10 +municipality, roll and year, the assessment ratio falls by 34\% per
11 +log-point of price in the descriptive fixed-effects estimate, and by 8\%
12 +under the most conservative measurement-error correction available.
13 +Ninety-five percent of municipalities fail the IAAO vertical-equity
14 +standard, ninety-nine percent fail its uniformity standard, and the median
15 +dwelling in the bottom local price decile pays roughly two thirds more
16 +property tax than uniform assessment would imply, while the top decile
17 +pays less. The inequity concentrates where mass appraisal is hardest ---
18 +old houses, plexes, land-heavy and luxury properties, thin markets ---
19 +doubles when triennial rolls fall behind a booming market, and disappears
20 +almost nowhere except Montr\'eal.
21 +
22 +These findings reframe the presumption that centralized, professionally
23 +regulated assessment systems are immune to the pathologies documented in
24 +the fragmented U.S. system. Quebec has uniform statutes, certified
25 +evaluators and statutory market-vintage synchronization --- and produces
26 +regressivity of U.S. magnitude anyway. The binding constraint is not
27 +governance but valuation technology and revaluation frequency, which is
28 +in fact encouraging: cycle length, pooled assessment services and
29 +vertical audit standards are policy variables, and inexpensive ones
30 +relative to the redistribution at stake.
31 +
32 +The matched sale--roll architecture built here supports a research agenda
33 +beyond this audit: linking assessment gaps to neighbourhood
34 +socio-demographics, exploiting the discrete arrival of new rolls to study
35 +price anchoring, and using the land--building decomposition to measure
36 +land-value dynamics at the parcel level. We pursue these in companion
37 +work.
added paper/sections/data.tex +101 −0
@@ -0,0 +1,101 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Data and sample construction}
4 +\label{sec:data}
5 +
6 +\subsection{Sources and matching}
7 +
8 +We start from a compiled registry of 745{,}119 residential-market
9 +transactions recorded in Quebec between January 2021 and July 2026, each
10 +carrying the sale price, sale date, civic address, geographic coordinates,
11 +and a listing-derived property type. Each transaction has been matched at
12 +the parcel level to the municipal assessment roll in force on the sale date.
13 +The match keys on geographic proximity between the transaction's coordinates
14 +and the roll unit's coordinates and is validated against the roll's recorded
15 +value; a composite score (maximum 220) summarizes the quality of the
16 +address, distance and value agreement. Matches are extremely tight: the
17 +median distance between the transaction and the matched roll unit is
18 +0.6~metres, and every observation retained in the estimation sample
19 +reproduces the roll's assessed value exactly.
20 +
21 +From the roll we observe the taxable value of the property
22 +($AV$, \texttt{valeur immeuble}), its land and building components, lot
23 +area, total floor area, year of construction, number of dwelling units, the
24 +standardized use code (CUBF), the roll vintage, and the statutory
25 +market-condition reference date discussed in Section~\ref{sec:inst}.
26 +
27 +\subsection{Sample restrictions}
28 +
29 +Table~\ref{tab:sumstats} describes the estimation sample; the selection
30 +cascade is as follows. We keep sales of residential use codes ---
31 +dwellings (CUBF 1000), cottages (1100), mobile homes (1211) and other
32 +residential (1990) --- which removes vacant land, commercial property and
33 +construction-in-progress (672{,}276 sales remain). We require a
34 +high-confidence roll match (distance $\le 50$~m and score $\ge 150$;
35 +568{,}711 sales), a positive assessed value and a price of at least
36 +\$50{,}000 --- the floor of the source registry, which also screens out
37 +most non-arm's-length transfers. Assessment ratios $r_i = AV_i/SP_i$ are
38 +trimmed at the 1st and 99th percentiles \emph{within each roll vintage}, so
39 +that the mechanical drift of ratio levels across vintages is not trimmed
40 +asymmetrically (557{,}325 sales). Finally, since all estimates compare
41 +sales within a municipality $\times$ roll $\times$ sale-year block
42 +(``cell''), we require at least 20 sales per cell. The estimation sample
43 +contains \textbf{522{,}769 sales} in 625 municipalities and 2{,}884 cells:
44 +345{,}053 single-family homes, 81{,}693 plexes (2--5 units), 81{,}461
45 +condominiums, 9{,}287 cottages and 4{,}701 mobile homes.
46 +
47 +\begin{table}[t]
48 +\centering
49 +\begin{threeparttable}
50 +\caption{Summary statistics, estimation sample}
51 +\label{tab:sumstats}
52 +\small
53 +\input{../results/tables/summary_stats}
54 +\begin{tablenotes}[flushleft]\footnotesize
55 +\item \textit{Notes:} 522{,}769 residential sales, January 2021 -- July
56 +2026, matched at the parcel level to the assessment roll in force at the
57 +sale date. The assessment ratio is assessed value divided by sale price.
58 +Roll lag is the number of months between the roll's statutory
59 +market-condition reference date (July 1) and the sale date. The assessed
60 +land share is the roll's land value divided by total assessed value.
61 +\end{tablenotes}
62 +\end{threeparttable}
63 +\end{table}
64 +
65 +\subsection{The raw pattern}
66 +
67 +The median assessment ratio is 0.78: the typical dwelling sells for about
68 +28\% more than its rolled value, the expected imprint of a rising market on
69 +back-dated rolls. Figure~\ref{fig:ratiodist} shows the distribution and its
70 +decomposition by roll lag: sales occurring within two years of the
71 +reference date centre near 0.87, while sales more than four years out
72 +centre near 0.64 --- the mechanical staleness gradient that our fixed
73 +effects absorb. Figure~\ref{fig:time} traces the same mechanics in
74 +calendar time: each roll vintage enters near parity with the market it was
75 +referenced on, then drifts down as prices rise, and the 2022--2023 rate
76 +shock is visible as a flattening of the drift. Everything that follows
77 +nets out this timing structure and asks a sharper question: \emph{within} a
78 +given municipality, roll, and year, do cheap and expensive homes face the
79 +same ratio?
80 +
81 +\begin{figure}[t]
82 +\centering
83 +\includegraphics[width=\textwidth]{fig_ratio_dist.png}
84 +\caption{Assessment ratios. Panel A: distribution of $AV/SP$ across the
85 +estimation sample; the median is 0.78 and the dashed line marks parity.
86 +Panel B: kernel of the same distribution split by the number of months
87 +between the roll's market-condition reference date and the sale; older
88 +rolls sit systematically further below parity.}
89 +\label{fig:ratiodist}
90 +\end{figure}
91 +
92 +\begin{figure}[t]
93 +\centering
94 +\includegraphics[width=\textwidth]{fig_time.png}
95 +\caption{Median assessment ratio by sale month and roll vintage. Each line
96 +follows sales assessed under one triennial vintage (labelled by entry
97 +year); monthly medians with fewer than 100 sales are suppressed. Vintages
98 +enter near their reference-date market level and drift down as prices
99 +rise; the flattening after 2022 reflects the interest-rate correction.}
100 +\label{fig:time}
101 +\end{figure}
added paper/sections/discussion.tex +81 −0
@@ -0,0 +1,81 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Discussion}
4 +\label{sec:disc}
5 +
6 +\subsection{Mechanisms}
7 +
8 +The evidence assembles into a coherent mechanism story with three layers.
9 +
10 +\paragraph{1. Hedonic difficulty, not assessor idiosyncrasy.} The
11 +heterogeneity profile tracks the difficulty of the valuation problem with
12 +almost embarrassing fidelity: condominiums (homogeneous, comparable-rich)
13 +are nearly equitable; old houses, plexes, cottages and high-land-share
14 +properties (heterogeneous, comparable-poor, unanchored by construction
15 +costs) are severely regressive. This is the pattern predicted if assessors
16 +run reasonable hedonic models whose unexplained component is largest ---
17 +and most value-correlated --- where the housing bundle is hardest to price
18 +\citep{amornsiripanitch2022residential, gloudemans2011fundamentals,
19 +bostic2007land}. Regression toward the mean in any imperfect valuation
20 +model over-values the cheap tail and under-values the expensive tail;
21 +our quantile profile, with proportionality holding at the bottom and
22 +collapsing at the top ($\beta(0.90) = 0.49$), shows Quebec's failure is
23 +concentrated where comparables are thinnest.
24 +
25 +\paragraph{2. Staleness amplifies the gap.} The doubling of the
26 +province-wide PRB in 2021--2022 shows that triennial rolls interact
27 +perversely with fast markets: when prices move 30--40\% between reference
28 +dates, the cross-sectional dispersion of appreciation --- which is itself
29 +correlated with price segment --- loads directly into measured inequity.
30 +Jurisdictions cannot control housing cycles, but they control revaluation
31 +frequency; annual-cycle systems mechanically cap this channel
32 +\citep{berry2021reassessing, ross2012assessor}.
33 +
34 +\paragraph{3. Scale helps: the Montr\'eal exception.} Montr\'eal ---
35 +the largest sales sample, a dedicated in-house assessment service, dense
36 +comparable markets in every segment --- is the only large jurisdiction
37 +with progressive assessments, in all six years. Mid-sized and small
38 +municipalities, many relying on contracted regional evaluators with
39 +limited modelling capacity, are uniformly regressive. The thin-market
40 +mechanism of \citet{mcmillen2008thin} operates within a single provincial
41 +rulebook: identical statutes, divergent outcomes, sorted by market depth
42 +and assessment resources. We note one caveat: Montr\'eal's measured
43 +progressivity may partly reflect within-city composition (its cell is the
44 +whole city, pooling boroughs), and borough-level analysis is a natural
45 +extension.
46 +
47 +\subsection{Policy implications}
48 +
49 +Three levers follow directly from the diagnosis, in increasing order of
50 +ambition. First, \textbf{shorten the cycle}: moving from triennial to
51 +annual (or indexed) rolls would eliminate the staleness component that
52 +dominated 2021--2022; several U.S. states and British Columbia already
53 +operate annual cycles. Second, \textbf{pool assessment capacity}: the
54 +regressivity gradient by municipality size argues for regional or
55 +provincial mass-appraisal services --- scale is the cheapest known
56 +technology for assessment quality. Third, \textbf{audit vertically, not
57 +just horizontally}: Quebec's oversight regime monitors median ratios and
58 +CODs but sets no explicit PRB requirement; adding the IAAO vertical
59 +standard to the ministry's audit criteria, with published
60 +municipality-level statistics like those in this paper, would make the
61 +equity dimension visible and contestable. Because low-priced-segment
62 +owners appeal least \citep{avenancio2022assessment, plummer2014evidence},
63 +supply-side correction --- better models --- will do more than
64 +demand-side remedies.
65 +
66 +\subsection{Limitations}
67 +
68 +Four limitations bound the interpretation. First, sale prices below
69 +\$50{,}000 are absent from the source registry and some residual
70 +non-arm's-length transfers may survive our screens; the robustness
71 +battery (dropping sub-\$100k sales, tightening trims) shows the
72 +conclusions survive, but the bottom-decile tax-shift magnitude should be
73 +read as an upper bound on that decile. Second, our data cover 2021--2026,
74 +an unusually turbulent market; the within-market elasticity is stable
75 +across the window, but levels statistics from calmer periods would differ.
76 +Third, we observe no appeals, renovations between assessment and sale, or
77 +conditions of sale; some of what we call horizontal noise is genuine
78 +unobserved quality change. Fourth, without owner demographics we cannot
79 +speak to the distributional incidence across income or racial groups as
80 +\citet{avenancio2022assessment} do --- linking these assessments to census
81 +tract characteristics is the obvious next step.
added paper/sections/institutional.tex +63 −0
@@ -0,0 +1,63 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Institutional setting: property assessment in Quebec}
4 +\label{sec:inst}
5 +
6 +Quebec's municipal fiscal regime is governed by the \textit{Loi sur la
7 +fiscalit\'e municipale} (LFM) and operationalized by the province's
8 +assessment manual, the \textit{Manuel d'\'evaluation fonci\`ere du
9 +Qu\'ebec} \citep{lfm2026, mamh2024manuel}. Four features matter for the
10 +measurement design of this paper.
11 +
12 +\paragraph{Triennial rolls.} Every municipality's assessment roll is
13 +redrawn on a fixed three-year cycle by a municipal body or a contracted
14 +private firm under the responsibility of a chartered evaluator. The roll
15 +lists, for each assessment unit, the taxable value of the property and its
16 +decomposition into land and building components, along with the structural
17 +descriptors used in valuation (lot area, floor area, year of construction,
18 +number of dwelling units, physical configuration, and a standardized use
19 +code, the CUBF).
20 +
21 +\paragraph{A statutory market-condition date.} Article 46 of the LFM
22 +requires that the values entered on a roll reflect the state of the market
23 +\emph{eighteen months before} the roll takes effect: a roll entering force
24 +on January~1 of year $t$ must value every property as of July~1 of year
25 +$t-2$. This single reference date is printed on the roll itself and is
26 +common to every property in the municipality. Two implications follow.
27 +First, in a rising market the \emph{level} of assessment ratios drifts
28 +mechanically below one as sales occur further from the reference date ---
29 +between 18 and 54 months elapse between the reference date and a sale, 36
30 +months at the median in our sample. This drift is a feature of the system,
31 +not an inequity, and our empirical design absorbs it entirely with
32 +municipality~$\times$~roll~$\times$~sale-year fixed effects. Second, and
33 +crucially, \emph{within} such a block every property shares the same market
34 +vintage, so cross-sectional patterns in ratios cannot be attributed to
35 +timing.
36 +
37 +\paragraph{Uniform taxation of the rolled value.} The municipal levy on a
38 +residential property is the rolled taxable value multiplied by the
39 +municipal rate (plus school taxes levied on the same base). There are no
40 +assessment-growth caps, homestead exemptions, or acquisition-value rules of
41 +the Californian or Floridian type: relative taxable values within a
42 +municipality equal relative assessed values. This makes the mapping from
43 +assessment error to tax-burden redistribution exact --- a property assessed
44 +10\% above the jurisdiction's median ratio pays 10\% more tax than uniform
45 +assessment would imply --- and motivates the tax-shift calculation of
46 +Section~\ref{sec:results}.
47 +
48 +\paragraph{Oversight and appeal.} The Ministry of Municipal Affairs (MAMH)
49 +prescribes methods and audits rolls; owners may request an administrative
50 +review and appeal to the Tribunal administratif du Qu\'ebec. Appeal rates
51 +for residential property are low. Unlike several U.S. jurisdictions
52 +studied in the literature \citep{plummer2014evidence,
53 +avenancio2022assessment}, Quebec's appeal system plays a minor quantitative
54 +role for the housing stock at large, which makes the valuation model
55 +itself --- rather than post-assessment litigation --- the natural locus of
56 +any inequity we measure.
57 +
58 +Taken together, these institutions imply that Quebec should be a
59 +\emph{best-case} environment for assessment equity: uniform provincial
60 +methodology, professional certification, statutory synchronization of
61 +market vintage, and a tax that consumes the rolled value without
62 +exemption-driven distortions. The magnitude of the inequity we document
63 +below should be read against this backdrop.
added paper/sections/introduction.tex +127 −0
@@ -0,0 +1,127 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Introduction}
4 +\label{sec:intro}
5 +
6 +The property tax is the fiscal backbone of Canadian local government: it
7 +finances roughly two thirds of municipal budgets and is, by statute, an
8 +\emph{ad valorem} tax --- every dwelling in a municipality is meant to be
9 +taxed in strict proportion to its market value. That proportionality rests
10 +entirely on the quality of the assessment roll. If assessors systematically
11 +overvalue inexpensive homes relative to expensive ones, the legal tax rate
12 +becomes a fiction: the effective tax rate falls with wealth, and the
13 +resulting redistribution --- from modest neighbourhoods toward affluent ones
14 +--- occurs silently, without any legislative decision, embedded in a
15 +technical document that few taxpayers ever contest. A rapidly growing
16 +literature documents exactly this pattern in the United States, where
17 +assessment regressivity has been measured at national scale
18 +\citep{berry2021reassessing, avenancio2022assessment,
19 +amornsiripanitch2022residential}. Whether the same pathology afflicts
20 +Canadian assessment systems --- centralized, professionally supervised, and
21 +widely presumed to be of high quality --- is essentially unknown.
22 +
23 +This paper provides the first province-wide answer for Quebec. We assemble
24 +522{,}769 residential transactions recorded between January 2021 and July
25 +2026 and match each sale, at the parcel level, to the triennial municipal
26 +assessment roll in force on the day of the sale. The match is performed on
27 +geographic coordinates and validated against the roll's recorded value; the
28 +median match distance is under one metre. The resulting file couples every
29 +sale price with the exact taxable value that generated the owner's property
30 +tax bill, together with the roll's decomposition of that value into land and
31 +building components, structural descriptors (lot area, floor area, year
32 +built, number of units), and the statutory market-condition reference date
33 +of the roll. The data span 625 municipalities --- from Montr\'eal
34 +(79{,}581 usable sales) to towns with barely a hundred --- and a housing
35 +cycle of unusual amplitude: the post-pandemic boom, the 2022--2023 interest
36 +rate shock, and the subsequent recovery.
37 +
38 +Quebec's institutional design makes it an unusually clean laboratory for
39 +equity measurement. Every municipality's roll is redone on a fixed
40 +three-year cycle, and by law (art.~46, \textit{Loi sur la fiscalit\'e
41 +municipale}) the values entered on a roll must reflect market conditions
42 +eighteen months before the roll takes effect --- a single, known reference
43 +date shared by every property in the municipality
44 +\citep{lfm2026, mamh2024manuel}. Within a municipality $\times$ roll
45 +$\times$ sale-year block, therefore, every assessment embodies the same
46 +market vintage, and any systematic relationship between assessment ratios
47 +and prices inside such a block is inequity, not timing. Our empirical design
48 +exploits exactly this structure: all regression estimates absorb 2{,}884
49 +municipality~$\times$~roll~$\times$~year fixed effects, so that vertical
50 +inequity is identified purely from comparisons between cheap and expensive
51 +dwellings facing the same assessor, the same roll, and the same market
52 +moment.
53 +
54 +Three findings emerge. First, assessment regressivity in Quebec is
55 +pervasive, large, and statistically unambiguous. The elasticity of the
56 +assessment ratio with respect to the sale price --- zero under proportional
57 +assessment --- is $-0.34$ (s.e.\ $0.03$) in the fixed-effects log-log
58 +regression. Because sale prices measure market value with noise, part of
59 +that estimate reflects mechanical attenuation \citep{kochin1982vertical,
60 +clapp1990new}; a rank-based instrumental-variables estimator in the spirit
61 +of \citet{clapp1990new} that purges this bias still yields $-0.08$
62 +(s.e.\ $0.02$). Under the IAAO ratio-study standards used by assessment
63 +authorities across North America \citep{iaao2013standard}, 95\% of Quebec
64 +municipalities fall outside the acceptable band for price-related bias and
65 +99\% exceed the uniformity (COD) ceiling. Strikingly, Montr\'eal --- the
66 +province's largest and best-resourced assessment jurisdiction --- is the
67 +\emph{only} major market whose assessments are progressive.
68 +
69 +Second, the inequity has a clear anatomy. Regressivity is roughly four times
70 +stronger for single-family homes and plexes than for condominiums, whose
71 +quasi-homogeneous units are easy to mass-appraise; it rises steeply with
72 +building age and with the assessed land share of the property, consistent
73 +with the difficulty of valuing land and depreciated structures
74 +\citep{bostic2007land, gloudemans2011fundamentals}; and it is worse in small
75 +municipalities, echoing the thin-market mechanism of \citet{mcmillen2008thin}.
76 +The quantile profile is equally telling: the log-log slope
77 +falls from $0.87$ at the first decile of the conditional value distribution
78 +to $0.49$ at the ninth, so the failure of proportionality is concentrated at
79 +the top --- expensive homes are not merely under-assessed, they are
80 +under-assessed at an accelerating rate.
81 +
82 +Third, the stakes are material. Within a taxing jurisdiction the levy is
83 +proportional to assessed value, so a property assessed above the
84 +jurisdiction median ratio pays exactly that percentage more tax than uniform
85 +assessment would imply. The median dwelling in the bottom within-market
86 +price decile pays roughly 65\% more property tax than under uniform
87 +assessment; the median dwelling in the top decile pays about 5\% less. Put
88 +differently, the effective tax schedule that Quebec's assessment machinery
89 +delivers is regressive enough to undo, within each municipality, a
90 +substantial share of whatever progressivity the rest of the fiscal system
91 +achieves --- a finding that complements \citet{carbonnier2024property}, who
92 +documents the regressivity of Quebec's property tax relative to income using
93 +survey data, but who could not observe the assessment channel isolated here.
94 +
95 +We also show \emph{when} the gap opens. Assessment ratios drift mechanically
96 +between reference dates, and the province-wide price-related bias doubles in
97 +2021--2022, precisely when the post-pandemic boom pulled market prices away
98 +from rolls anchored in 2018--2020 conditions --- direct evidence that
99 +infrequent revaluation is a first-order driver of measured inequity, as
100 +conjectured in the U.S. literature \citep{berry2021reassessing,
101 +ross2012assessor}. Because the diagnosis singles out stale rolls, thin
102 +markets, and hard-to-value property types --- rather than assessor
103 +discretion alone --- it maps directly into policy: shorter revaluation
104 +cycles, pooled assessment services for small municipalities, and targeted
105 +review of high-land-share and older properties.
106 +
107 +Beyond the Canadian evidence gap, the paper makes two methodological
108 +contributions to the ratio-study literature. It is, to our knowledge, the
109 +first large-scale equity study to exploit a statutory single-date reference
110 +regime to separate timing drift from genuine vertical inequity by design
111 +rather than by econometric correction; and it implements the full modern
112 +test battery --- IAAO diagnostics with bootstrap inference
113 +\citep{iaao2013standard}, the classical regression tests
114 +\citep{paglin1972equity, cheng1974property}, measurement-error-robust IV
115 +\citep{clapp1990new}, and quantile profiles \citep{mcmillen2020assessment}
116 +--- on more than half a million sales, allowing precise subgroup estimates
117 +that smaller samples cannot support.
118 +
119 +The remainder of the paper proceeds as follows. Section~\ref{sec:lit}
120 +positions the paper in the ratio-study and property-tax-equity literatures.
121 +Section~\ref{sec:inst} describes Quebec's assessment institutions.
122 +Section~\ref{sec:data} presents the data and the matched sample.
123 +Section~\ref{sec:method} lays out the diagnostics and econometric
124 +specifications. Section~\ref{sec:results} reports the results,
125 +Section~\ref{sec:robust} the robustness battery, Section~\ref{sec:disc}
126 +discusses mechanisms and policy implications, and Section~\ref{sec:concl}
127 +concludes.
added paper/sections/literature.tex +100 −0
@@ -0,0 +1,100 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Related literature}
4 +\label{sec:lit}
5 +
6 +\subsection{Measuring vertical inequity: from ratio studies to modern tests}
7 +
8 +The empirical study of assessment equity is nearly as old as the modern
9 +property tax. Its workhorse is the \emph{sales ratio study}: for each sale
10 +$i$, compute the ratio $r_i = AV_i/SP_i$ of assessed value to sale price and
11 +ask whether $r_i$ is uniform across the value distribution. The
12 +practitioner's canon --- codified in the IAAO \textit{Standard on Ratio
13 +Studies} \citep{iaao2013standard} and the mass-appraisal manuals of
14 +\citet{eckert1990property} and \citet{gloudemans2011fundamentals} ---
15 +summarizes a jurisdiction with the median ratio, the coefficient of
16 +dispersion (COD) for horizontal uniformity, and the price-related
17 +differential (PRD) or, since 2013, the coefficient of price-related bias
18 +(PRB) for vertical equity. These diagnostics discipline assessment practice
19 +across North America, and we report all of them, with bootstrap confidence
20 +intervals, for every Quebec municipality with sufficient sales.
21 +
22 +The academic literature grew out of dissatisfaction with those summary
23 +measures. \citet{paglin1972equity} proposed regressing assessed value on
24 +sale price in levels and reading regressivity off a positive intercept;
25 +\citet{cheng1974property} moved the test to logarithms, where the slope
26 +$\beta$ has the clean interpretation of an elasticity and $\beta<1$ signals
27 +regressivity. Subsequent work refined the specification menu ---
28 +\citet{bell1984administrative} and \citet{sunderman1990testing} allowed
29 +splines and structural breaks, and \citet{sirmans1995vertical} surveyed the
30 +proliferating test battery. A decisive critique came from
31 +\citet{kochin1982vertical} and \citet{kennedy1984unfair}: because the sale
32 +price is itself a noisy measure of market value, the log-log slope is
33 +attenuated toward zero even under perfectly proportional assessment ---
34 +ratio studies are biased \emph{toward} finding regressivity.
35 +\citet{clapp1990new} answered with a rank-based instrumental-variables
36 +estimator whose coarse instrument is nearly orthogonal to transitory price
37 +noise; \citet{goolsby1997assessment} and \citet{mcmillen2020assessment}
38 +document how severely the correction can matter, and
39 +\citet{quintos2020prb} extends the toolkit with machine-learning
40 +diagnostics. Our design follows this lesson to the letter: we report the
41 +na\"ive estimates, the Clapp IV, and quantile profiles
42 +\citep{mcmillen2020assessment} side by side, and treat the IV as the lower
43 +bound on true regressivity.
44 +
45 +\subsection{Evidence: pervasive regressivity, mostly documented in the U.S.}
46 +
47 +Substantively, the modern consensus is that assessment regressivity is the
48 +rule rather than the exception. \citet{berry2021reassessing} computes ratio
49 +statistics for essentially every U.S. county and finds that the
50 +lowest-decile home within a jurisdiction faces an effective tax rate roughly
51 +double that of the top decile; \citet{avenancio2022assessment} show in the
52 +\textit{QJE} that the same machinery generates a 10--13\% assessment gap
53 +against Black and Hispanic homeowners, driven partly by unpriced
54 +neighbourhood attributes and partly by differential appeals;
55 +\citet{amornsiripanitch2022residential} attributes much of the gradient to
56 +assessors' inability to capture unobserved quality that scales with price.
57 +Earlier strands documented the same pattern city by city ---
58 +\citet{engle1975deassessment} in Boston, \citet{baar1981property} across
59 +low-income neighbourhoods, \citet{mcmillen2011assessment} and
60 +\citet{mcmillen2008thin} in Illinois, where thin markets and infrequent
61 +reassessment emerge as structural drivers, \citet{hodge2017assessment} in
62 +collapsing Detroit, and \citet{plummer2014evidence} and
63 +\citet{ihlanfeldt2023appraisal} on the role of appeals and exemptions.
64 +\citet{ross2012assessor} shows regressivity responds to the institutional
65 +incentives of assessors themselves. The mechanism menu that emerges ---
66 +stale valuations, hard-to-value heterogeneous properties, thin markets,
67 +asymmetric appeals --- guides our heterogeneity analysis directly.
68 +
69 +\subsection{Canada: a conspicuous gap}
70 +
71 +For Canada the cupboard is nearly bare. Ontario's assessment corporation
72 +publishes an internal vertical-equity review of its own values
73 +\citep{mpac2022vertical}, and \citet{found2017property} compare tax
74 +\emph{rates} across cities, but neither measures sale-level equity.
75 +For Quebec, \citet{carbonnier2024property} establishes with survey microdata
76 +that property tax payments are steeply regressive relative to
77 +\emph{income}; the assessment channel --- whether the tax base itself is
78 +mismeasured against \emph{market value} --- has never been examined at
79 +scale, for Quebec or for any Canadian province. This is the gap the present
80 +paper fills. The Canadian case is of independent interest precisely because
81 +its institutions differ from the fragmented U.S. county system on the
82 +dimensions the U.S. literature blames: Quebec assessment is governed by a
83 +uniform provincial statute and manual \citep{lfm2026, mamh2024manuel},
84 +performed by certified professional evaluators, and synchronized to a
85 +statutory market-condition date. Finding large regressivity \emph{despite}
86 +this apparatus sharpens the interpretation considerably: the problem is not
87 +lax governance but the intrinsic difficulty of mass appraisal, compounded by
88 +triennial staleness.
89 +
90 +\subsection{Hedonic foundations}
91 +
92 +Finally, the paper connects to the hedonic tradition. Mass appraisal is
93 +applied hedonics \citep{rosen1974hedonic, malpezzi2003hedonic}: the
94 +assessor's model prices a bundle of structural and locational attributes,
95 +and equity failures are hedonic specification failures --- unpriced
96 +land-share gradients \citep{bostic2007land}, depreciation curvature, or
97 +neighbourhood effects that Quebec practitioners have long modelled in the
98 +Quebec City market \citep{desrosiers2000hedonic}. Reading our subgroup
99 +estimates through this lens turns an audit into a diagnosis: the assessment
100 +gap is largest exactly where the hedonic problem is hardest.
added paper/sections/methodology.tex +108 −0
@@ -0,0 +1,108 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Methodology}
4 +\label{sec:method}
5 +
6 +Let $AV_i$ denote the assessed value of property $i$ on the roll in force
7 +at its sale, $SP_i$ its sale price, and $r_i = AV_i/SP_i$ the assessment
8 +ratio. Under perfectly proportional (vertically equitable) assessment,
9 +$\mathbb{E}[r_i \mid SP_i]$ is constant. All tests below ask, in different
10 +ways, whether $r_i$ instead declines with value.
11 +
12 +\subsection{IAAO ratio-study diagnostics}
13 +
14 +For any group of sales we report the four statistics of the IAAO
15 +\textit{Standard on Ratio Studies} \citep{iaao2013standard}. The
16 +\emph{median ratio} measures the assessment level. The \emph{coefficient of
17 +dispersion},
18 +$\mathrm{COD} = 100 \cdot \operatorname{mean}\!\left(|r_i -
19 +\tilde r|\right) / \tilde r$ with $\tilde r$ the median ratio, measures
20 +horizontal uniformity; the standard deems residential CODs above 15
21 +unacceptable. The \emph{price-related differential},
22 +$\mathrm{PRD} = \bar r \,/\, (\sum_i AV_i / \sum_i SP_i)$, compares the
23 +unweighted and value-weighted mean ratios; PRD~$>1.03$ indicates
24 +regressivity. Because the PRD is sensitive to outliers, the standard's
25 +preferred vertical measure is the \emph{coefficient of price-related bias}
26 +(PRB), the slope $b$ in
27 +\begin{equation}
28 +\frac{r_i - \tilde r}{\tilde r}
29 + \;=\; a + b \cdot \log_2\!\Big(\tfrac{1}{2}SP_i +
30 + \tfrac{1}{2}\,AV_i/\tilde r\Big) + u_i ,
31 +\label{eq:prb}
32 +\end{equation}
33 +which measures the proportional change in the ratio per doubling of value;
34 +the acceptable band is $[-0.05, 0.05]$. We compute percentile-bootstrap
35 +confidence intervals for all four statistics. Because ratio levels drift
36 +with roll staleness, municipality-level diagnostics are computed within
37 +municipality~$\times$~sale-year blocks --- inside which a single roll is in
38 +force --- and aggregated across years by the median.
39 +
40 +\subsection{Regression tests with market-timing fixed effects}
41 +
42 +Our workhorse is the log-log specification of \citet{cheng1974property},
43 +\begin{equation}
44 +\ln AV_i \;=\; \alpha_{c(i)} + \beta \, \ln SP_i + \varepsilon_i ,
45 +\label{eq:cheng}
46 +\end{equation}
47 +where $c(i)$ indexes the municipality~$\times$~roll~$\times$~sale-year cell
48 +of sale $i$ and the $\alpha_c$ are 2{,}884 absorbed fixed effects.
49 +Proportionality implies $\beta = 1$; we report
50 +$\gamma \equiv \beta - 1$, the elasticity of the assessment \emph{ratio}
51 +with respect to price ($\gamma<0$: regressive). The fixed effects guarantee
52 +that $\gamma$ is identified only from comparisons of dwellings assessed by
53 +the same authority, on the same roll vintage, and sold in the same year ---
54 +purging the staleness drift, municipal composition, and aggregate market
55 +movements in one stroke. For completeness we also report the pooled
56 +regression without fixed effects and the levels test of
57 +\citet{paglin1972equity}. Inference is clustered at the municipality level
58 +throughout (625 clusters).
59 +
60 +\subsection{Measurement error and the Clapp instrument}
61 +
62 +Sale prices measure market value with idiosyncratic noise --- bilateral
63 +bargaining, unobserved conditions of sale --- so OLS on
64 +equation~\eqref{eq:cheng} suffers attenuation bias: $\hat\beta < 1$ even
65 +under proportional assessment \citep{kochin1982vertical, kennedy1984unfair}.
66 +Following \citet{clapp1990new}, we instrument $\ln SP_i$ with a coarse rank
67 +variable $Z_i \in \{-1, 0, +1\}$ that flags sales in the bottom or top
68 +third of \emph{both} the within-cell $\ln AV$ and $\ln SP$ distributions.
69 +Because $Z_i$ retains only ordinal information agreed on by both measures of
70 +value, it is (nearly) orthogonal to the transitory component of either, and
71 +the resulting two-stage least-squares estimate of $\beta$ is consistent
72 +under classical measurement error. The demeaned-within-cell implementation
73 +preserves the fixed-effects structure. Throughout the paper we treat
74 +$\gamma_{\text{IV}}$ as a conservative lower bound on regressivity and
75 +$\gamma_{\text{FE}}$ as the descriptive upper bound; the truth lies between.
76 +
77 +\subsection{Quantile profile and heterogeneity}
78 +
79 +Averaging can hide where proportionality fails. We estimate
80 +equation~\eqref{eq:cheng} by quantile regression on within-cell demeaned
81 +variables at $\tau \in \{0.10, 0.25, 0.50, 0.75, 0.90\}$
82 +\citep{mcmillen2020assessment}, tracing $\beta(\tau)$ across the
83 +conditional distribution of assessed values. We then re-estimate the
84 +fixed-effects model on subsamples --- property class, building-age bands,
85 +assessed-land-share bands, roll-lag bands, municipality size, and sale year
86 +--- keeping only cells that retain at least 20 sales, to locate the
87 +inequity where the mass-appraisal problem is hardest.
88 +
89 +\subsection{Horizontal inequity}
90 +
91 +Vertical tests concern the \emph{mean} of $r_i$ given value; horizontal
92 +equity concerns its \emph{dispersion} among comparable properties
93 +\citep{allen2002measuring, sirmans2008vertical}. Beyond the COD, we ask
94 +who receives noisy assessments: we regress the absolute deviation of a
95 +sale's log ratio from its cell median,
96 +$|\ln r_i - \operatorname{med}_{c(i)} \ln r|$, on property characteristics
97 +(age, land share, property-class indicators) with cell fixed effects.
98 +
99 +\subsection{The implied tax shift}
100 +
101 +Because Quebec taxes the rolled value without exemptions or caps
102 +(Section~\ref{sec:inst}), a property whose ratio exceeds its jurisdiction's
103 +median by $x\%$ pays exactly $x\%$ more tax than uniform assessment would
104 +imply. For each sale we compute the relative assessment error
105 +$e_i = r_i / \operatorname{med}_{c(i)}(r) - 1$ and average it by
106 +within-cell sale-price decile. This translates the econometrics into the
107 +policy-relevant object: the percentage over- or under-payment of property
108 +tax by position in the local price distribution.
added paper/sections/results.tex +298 −0
@@ -0,0 +1,298 @@
1 +% Author: Simon-Pierre Boucher — contact@spboucher.ai
2 +% ============================================================================
3 +\section{Results}
4 +\label{sec:results}
5 +
6 +\subsection{Province-wide diagnostics}
7 +
8 +Table~\ref{tab:iaao} reports the IAAO statistics for the full sample and by
9 +sale year. Three facts stand out. First, uniformity is poor everywhere: the
10 +province-wide COD is 28.5, and even within municipality-year blocks the
11 +median municipality posts a COD of 26 --- nearly twice the IAAO ceiling of
12 +15 for residential property; 99\% of municipalities exceed it
13 +(Figure~\ref{fig:cod}). Second, every vertical measure points the same way:
14 +the PRD is 1.072 (acceptable range 0.98--1.03) and the PRB is $-0.029$ with
15 +a bootstrap confidence interval far from zero --- ratios fall by about 3\%
16 +of the median with every doubling of value. Third, the time pattern is
17 +diagnostic: the PRB collapses to $-0.104$ and $-0.117$ in 2021 and 2022 ---
18 +when the boom pulled prices away from rolls referenced on 2018--2020
19 +markets --- and shrinks to $-0.002$ in 2024 before widening again. Vertical
20 +inequity is not a fixed institutional constant; it breathes with the gap
21 +between the market and the roll's vintage.
22 +
23 +\begin{table}[t]
24 +\centering
25 +\begin{threeparttable}
26 +\caption{IAAO ratio-study diagnostics, province-wide}
27 +\label{tab:iaao}
28 +\small
29 +\input{../results/tables/iaao}
30 +\begin{tablenotes}[flushleft]\footnotesize
31 +\item \textit{Notes:} Median assessment ratio, coefficient of dispersion
32 +(COD), price-related differential (PRD) and coefficient of price-related
33 +bias (PRB), computed on the estimation sample; 95\% percentile-bootstrap
34 +confidence intervals (200 replications) in brackets. IAAO acceptable
35 +ranges: COD $\le 15$ (single-family residential), PRD $\in [0.98, 1.03]$,
36 +PRB $\in [-0.05, 0.05]$.
37 +\end{tablenotes}
38 +\end{threeparttable}
39 +\end{table}
40 +
41 +\begin{figure}[t]
42 +\centering
43 +\includegraphics[width=\textwidth]{fig_cod.png}
44 +\caption{Horizontal uniformity. Panel A: distribution of municipality-level
45 +CODs (median across sale-year blocks); the IAAO ceiling for residential
46 +property is 15. Panel B: COD against the number of sales in the
47 +municipality; dispersion is worst in the thinnest markets.}
48 +\label{fig:cod}
49 +\end{figure}
50 +
51 +Table~\ref{tab:cities} disaggregates the ten largest markets.
52 +Regressivity is significant in nine of them --- Sherbrooke ($-0.39$),
53 +Trois-Rivi\`eres ($-0.32$) and Terrebonne ($-0.29$) are the worst --- in
54 +every single sale year. The exception is Montr\'eal, whose PRB of $+0.07$
55 +makes it the lone \emph{progressive} large jurisdiction in the province, in
56 +all six years. We return to this contrast in Section~\ref{sec:disc}.
57 +Figure~\ref{fig:map} maps the municipal estimates: regressive (red)
58 +municipalities carpet the province, with the Montr\'eal agglomeration a
59 +solitary blue island, and Figure~\ref{fig:prbmuni} shows the distribution:
60 +99\% of the 261 municipalities with at least 100 usable sales have a
61 +negative PRB, and 95\% fall below the IAAO band.
62 +
63 +\begin{table}[t]
64 +\centering
65 +\begin{threeparttable}
66 +\caption{Assessment equity in the ten largest markets}
67 +\label{tab:cities}
68 +\small
69 +\input{../results/tables/iaao_cities}
70 +\begin{tablenotes}[flushleft]\footnotesize
71 +\item \textit{Notes:} Statistics computed within municipality
72 +$\times$ sale-year blocks (a single roll in force per block) and
73 +aggregated across years by the median; $n$ is the total number of sales.
74 +The last column is the share of the six sale years in which the
75 +municipality's PRB is negative.
76 +\end{tablenotes}
77 +\end{threeparttable}
78 +\end{table}
79 +
80 +\begin{figure}[t]
81 +\centering
82 +\includegraphics[width=0.72\textwidth]{fig_prb_muni.png}
83 +\caption{Distribution of municipality-level PRB across the 261
84 +municipalities with at least 100 usable sales. The shaded band is the IAAO
85 +acceptable range $[-0.05, 0.05]$.}
86 +\label{fig:prbmuni}
87 +\end{figure}
88 +
89 +\begin{figure}[t]
90 +\centering
91 +\includegraphics[width=\textwidth]{fig_map.png}
92 +\caption{The geography of vertical inequity. Municipality-level PRB
93 +(median across sale-year blocks); bubble area is proportional to the
94 +square root of the number of sales. Montr\'eal is the only large
95 +progressive jurisdiction.}
96 +\label{fig:map}
97 +\end{figure}
98 +
99 +\subsection{Regression estimates}
100 +
101 +Table~\ref{tab:vertical} presents the econometric core.
102 +Figure~\ref{fig:binscatter} shows the raw material: within
103 +municipality~$\times$~roll~$\times$~year cells, mean log assessment ratios
104 +fall monotonically --- and remarkably linearly through the central 90\% of
105 +the distribution --- as log prices rise. The pooled \citet{cheng1974property}
106 +elasticity is $\beta = 0.812$ (s.e.\ 0.029); absorbing the 2{,}884 cell
107 +fixed effects \emph{steepens} it to $\beta = 0.656$, i.e.\
108 +$\gamma_{\text{FE}} = -0.344$: within the same market and vintage, a home
109 +priced 10\% above its neighbours is assessed only about 6.6\% higher, so
110 +its ratio is 3.4\% lower. The levels test of \citet{paglin1972equity}
111 +agrees: the intercept is \$31{,}729 (s.e.\ \$5{,}378) --- inexpensive
112 +properties carry a fixed assessment premium.
113 +
114 +\begin{table}[t]
115 +\centering
116 +\begin{threeparttable}
117 +\caption{Vertical-inequity regressions}
118 +\label{tab:vertical}
119 +\small
120 +\input{../results/tables/vertical}
121 +\begin{tablenotes}[flushleft]\footnotesize
122 +\item \textit{Notes:} Dependent variable: $\ln AV$. Column (1): pooled
123 +OLS. Column (2): absorbing least squares with 2{,}884 municipality
124 +$\times$ roll $\times$ sale-year fixed effects. Column (3): within-cell
125 +2SLS using the \citet{clapp1990new} rank instrument
126 +$Z \in \{-1,0,+1\}$. Standard errors clustered by municipality (625
127 +clusters) in parentheses. Stars test $H_0\!: \beta = 1$ (proportional
128 +assessment); *** $p<0.01$.
129 +\end{tablenotes}
130 +\end{threeparttable}
131 +\end{table}
132 +
133 +\begin{figure}[t]
134 +\centering
135 +\includegraphics[width=0.72\textwidth]{fig_binscatter.png}
136 +\caption{Vertical inequity within markets. Mean of the within-cell demeaned
137 +log assessment ratio by vigintile of the within-cell demeaned log sale
138 +price; whiskers are 95\% confidence intervals (they are smaller than the
139 +markers). The fitted line is the sale-weighted least-squares slope.}
140 +\label{fig:binscatter}
141 +\end{figure}
142 +
143 +How much of this is measurement-error artefact? The \citet{clapp1990new}
144 +instrument delivers $\beta_{\text{IV}} = 0.917$ (s.e.\ 0.021):
145 +attenuation indeed accounts for the majority of the na\"ive gap, exactly
146 +as the critique of \citet{kochin1982vertical} predicts --- but the
147 +corrected elasticity remains four standard errors below one. Genuine
148 +regressivity of roughly $-0.08$ survives the harshest correction in the
149 +literature. An 8\% ratio penalty per log-point of value is economically
150 +large: across the interquartile price range within a typical market
151 +(roughly 0.8 log points), it generates a 6--7\% differential in effective
152 +tax rates from vertical inequity alone, before adding the much larger
153 +dispersion documented below.
154 +
155 +\subsection{Where proportionality fails: the quantile profile}
156 +
157 +Figure~\ref{fig:quantile} plots $\beta(\tau)$. The profile is strikingly
158 +asymmetric: $\beta$ is 0.87 at $\tau=0.10$ and 0.86 at $\tau=0.25$, then
159 +falls to 0.70 at $\tau=0.75$ and 0.49 at $\tau=0.90$
160 +(Table~\ref{tab:quantile} in the robustness section reports the
161 +coefficients). Assessment tracks the market tolerably well through the
162 +middle of the distribution and loses contact at the top: the most expensive
163 +homes within each market are under-assessed at an accelerating rate. This
164 +is the signature of hedonic truncation --- mass-appraisal models built on
165 +mid-market comparables extrapolate poorly into thin luxury segments
166 +\citep{amornsiripanitch2022residential, gloudemans2011fundamentals}.
167 +
168 +\begin{figure}[t]
169 +\centering
170 +\includegraphics[width=0.72\textwidth]{fig_quantile.png}
171 +\caption{Quantile profile of the Cheng elasticity. Quantile regressions of
172 +within-cell demeaned $\ln AV$ on demeaned $\ln SP$; the shaded band is the
173 +pointwise 95\% confidence interval. Reference lines mark proportionality
174 +($\beta=1$) and the FE and IV point estimates.}
175 +\label{fig:quantile}
176 +\end{figure}
177 +
178 +\subsection{The anatomy of regressivity}
179 +
180 +Figure~\ref{fig:het} and Table~\ref{tab:het} dissect
181 +$\gamma_{\text{FE}}$ by subsample, and the pattern reads like a map of
182 +mass-appraisal difficulty:
183 +
184 +\begin{itemize}
185 +\item \textbf{Property class.} Condominiums --- homogeneous units with
186 +abundant comparables --- show $\gamma = -0.12$, single-family homes
187 +$-0.45$ and plexes $-0.49$. The assessor's problem, not the assessor's
188 +jurisdiction, drives the gradient.
189 +\item \textbf{Building age.} Regressivity deepens from $-0.30$ (under 20
190 +years) to $-0.43$ (over 60): depreciation and renovation heterogeneity are
191 +hard to observe from the roll.
192 +\item \textbf{Land share.} The starkest gradient: $-0.26$ where land is
193 +under 20\% of assessed value versus $-0.50$ where it exceeds 40\%.
194 +Land is the component without construction-cost anchoring
195 +\citep{bostic2007land}, and properties whose value is mostly land are
196 +assessed worst.
197 +\item \textbf{Municipality size.} Large markets ($>$10k sales) do
198 +better ($-0.27$) than mid-sized ones ($-0.41$), consistent with
199 +\citet{mcmillen2008thin}.
200 +\item \textbf{Stability.} Estimates are remarkably stable across sale
201 +years ($-0.32$ to $-0.38$) and roll lags --- unlike the \emph{level}
202 +statistics, the within-market elasticity is a structural feature of the
203 +valuation technology, not of the cycle.
204 +\end{itemize}
205 +
206 +\begin{figure}[p]
207 +\centering
208 +\includegraphics[width=0.85\textwidth]{fig_heterogeneity.png}
209 +\caption{Heterogeneity of the within-market elasticity
210 +$\gamma$. Each point is a separate fixed-effects estimate of
211 +equation~\eqref{eq:cheng} on the indicated subsample; whiskers are 95\%
212 +confidence intervals with municipality-clustered standard errors.}
213 +\label{fig:het}
214 +\end{figure}
215 +
216 +\begin{table}[p]
217 +\centering
218 +\begin{threeparttable}
219 +\caption{Heterogeneity of vertical inequity}
220 +\label{tab:het}
221 +\small
222 +\input{../results/tables/heterogeneity}
223 +\begin{tablenotes}[flushleft]\footnotesize
224 +\item \textit{Notes:} Cheng fixed-effects estimates of
225 +$\gamma = \beta - 1$ by subsample; cells with fewer than 20 sales after
226 +masking are dropped. Municipality-clustered standard errors in
227 +parentheses. *, **, *** denote significance at 10\%, 5\%, 1\%.
228 +\end{tablenotes}
229 +\end{threeparttable}
230 +\end{table}
231 +
232 +\subsection{Horizontal inequity}
233 +
234 +Table~\ref{tab:horizontal} reports the dispersion regression. The mean
235 +absolute deviation of a sale's log ratio from its cell median is 0.188 ---
236 +the typical Quebec dwelling is assessed 19\% away from its market's norm,
237 +an enormous horizontal lottery consistent with the COD evidence. The
238 +deviation rises by 0.75~log points per decade of building age and by
239 +5.2~points for cottages, and falls by 5.5~points for condominiums.
240 +Old, idiosyncratic, land-heavy properties receive not only biased but
241 +\emph{noisy} valuations.
242 +
243 +\begin{table}[t]
244 +\centering
245 +\begin{threeparttable}
246 +\caption{Horizontal inequity: who receives noisy assessments?}
247 +\label{tab:horizontal}
248 +\small
249 +\input{../results/tables/horizontal}
250 +\begin{tablenotes}[flushleft]\footnotesize
251 +\item \textit{Notes:} Dependent variable:
252 +$|\ln r_i - \operatorname{med}_{c(i)} \ln r|$. Absorbing least squares
253 +with cell fixed effects; municipality-clustered standard errors.
254 +Omitted class: single-family. *, **, *** denote significance at 10\%,
255 +5\%, 1\%.
256 +\end{tablenotes}
257 +\end{threeparttable}
258 +\end{table}
259 +
260 +\subsection{The implied tax shift}
261 +
262 +Figure~\ref{fig:taxshift} and Table~\ref{tab:taxshift} translate the
263 +estimates into tax dollars. Within the median market, the median dwelling
264 +in the bottom price decile is assessed 65\% above the local norm --- and
265 +therefore pays 65\% more property tax than uniform assessment would imply.
266 +The overpayment falls to $+7\%$ in the second decile and crosses zero at
267 +the median; the top decile underpays by about 5\%. The redistribution is
268 +strongly convex: the burden of assessment error is overwhelmingly
269 +concentrated on the cheapest tenth of the housing stock --- precisely the
270 +segment where owners have the least capacity to appeal and the highest
271 +housing-cost burdens. The magnitudes rival those documented for the U.S.
272 +by \citet{berry2021reassessing}, in a system with none of the U.S.'s
273 +institutional fragmentation.
274 +
275 +\begin{figure}[t]
276 +\centering
277 +\includegraphics[width=0.85\textwidth]{fig_taxshift.png}
278 +\caption{The implied property-tax shift. Median relative assessment error
279 +$e_i = r_i/\operatorname{med}_{c(i)}(r) - 1$ by within-market sale-price
280 +decile. Because the levy is proportional to the rolled value, $e_i$ equals
281 +the percentage over- or under-payment relative to uniform assessment.}
282 +\label{fig:taxshift}
283 +\end{figure}
284 +
285 +\begin{table}[t]
286 +\centering
287 +\begin{threeparttable}
288 +\caption{Excess tax burden by within-market price decile}
289 +\label{tab:taxshift}
290 +\small
291 +\input{../results/tables/taxshift}
292 +\begin{tablenotes}[flushleft]\footnotesize
293 +\item \textit{Notes:} Relative assessment error by within-cell sale-price
294 +decile. The mean is sensitive to extreme low-price sales; the median is
295 +the preferred summary. Standard errors of the mean in parentheses.
296 +\end{tablenotes}
297 +\end{threeparttable}
298 +\end{table}
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