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# Limitations ledger — WP38

id limitation consequence handling
L-01 No price history in the source (current price per listing only) no temporal price analysis; H5 is cross-sectional declared ex ante (D-005); prospective collection plan in the paper
L-02 Listings are posted offers, not sales; disappearance ≠ sale; sold-out listings remain published no demand, revenue or employment inference wording rule; availability flag reported
L-03 Merchant location ≠ product origin; origin class is a store-level prior H6 untestable; "production" never inferred D-004; descriptive certification contrast labelled as not H6
L-04 229 live stores (71 692 listings, 19 % of the assortment sample) have no recoverable location, including the largest catalogues regional statistics describe located merchants only reported as "Inconnue"; excluded from inference; coverage audit
L-05 Region assignment combines three sources (municipality lookup, platform label, FSA centroid); rural FSA centroids are imprecise near borders some misassignment near borders (30 flagged conflicts) A-001; sensitivity with PIP-first and conflict-free samples
L-06 Rule-based category labels have 46 % precision against annotator consensus category-based statistics under rule labels are noisy A-002 classifier validated on a held-out audit; all category results under both labellings; confusion-reassignment robustness
L-07 Annotators are LLMs (two independent models) and adjudication was done by the research team, not by independent human coders label validity rests on inter-model agreement (95 %) and taxonomy definitions disclosed; disagreement files published
L-08 Discovery is a non-probability process favouring certified/association merchants; coverage per 1 000 businesses varies six-fold across regions regional comparisons confound economy and discovery representativeness audit; certification-source-only and no-Montréal variants
L-09 17 regions → very low power for H2 and H7-V3; ECI unstable at 17×20 H2 inconclusive; complexity not validated preregistered criteria; components only
L-10 Matching without GTIN; tier precision 0.98–1.00 among consensus pairs (lower bounds 0.90–0.92 counting non-consensus as failures) for A, B few false matches in H5 precision reported; comparable-variant restriction; sensitivity with C
L-11 Region effects in H5 identified only through groups spanning regions; one store = one region wide intervals; cannot separate region from store collinearity note; wild cluster bootstrap; stores per region reported
L-12 Connector caps (max 200 pages) truncate the largest catalogues; Wix/Ecwid coverage incomplete catalogue sizes of the largest stores under-measured noted; trimmed scheme T
L-13 Single snapshot; onboarding ended 2026-08-24; 10 weeks of listing dynamics H4 exploratory only temporal holdout; placebo
L-14 Power-law vs log-normal comparison uses a continuous log-normal on the discrete tail approximate model comparison stated; not a hypothesis
L-15 External covariates mix vintages (ISQ 2025/2024, Census 2021 on 2021 ER boundaries for Estrie/Montérégie) small concordance error for density ISQ columns used wherever available; manifest records vintages
L-16 H5 geographic joint test is dominated by one region/one reseller (Outaouais, 65 of 164 Wald points) and is sensitive to the bootstrap implementation no claim about regional price levels corrected bootstrap, LOO decomposition, status 'not supported'
L-17 Audit sample (500) was drawn before the mirror-domain rule: one listing belongs to a later-excluded sibling store; 92 % of audit stores also appear in the classifier training set (no merchant holdout) audit accuracy may be slightly optimistic for unseen merchants disclosed; labelled CSVs committed and hashed
Files · 2789bf667fc532fd5c04f52650ccc62606fd212e
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