1claim_id,claim,theory_or_empirical,supporting_keys,what_they_show,limitations_for_WP37,wp37_novelty2C1,"Equilibrium price dispersion for homogeneous goods arises from consumer search costs and heterogeneous information",theory,"stigler1961; salop1977; burdett1983; baye2006","Dispersed-price equilibria exist when some consumers are informed and others search sequentially or sample few prices","Theories are about transaction prices and identical goods; posted online prices at the banner level aggregate unknown stores","Measures dispersion on exactly matched items across Quebec banners from a single harmonised source; separates banner-level from within-banner (store-mixture) dispersion"3C2,"Temporary sales are an equilibrium mixed strategy to price-discriminate between informed/loyal and uninformed/shopper consumers",theory,"varian1980; pesendorfer2002; hendel2006; hendel2013; chevalier2019","Sales recur, are temporary and return to a stable reference price; storable-goods demand accumulation generates sale cycles","Requires quantities to identify demand; WP37 has posted prices only, so only the price-path implications are testable","Tests price-path implications (duration, depth, return-to-reference) on both storefront and circular channels"4C3,"Retail prices alternate between a sticky reference price and temporary sale prices; reference prices adjust rarely",empirical,"nakamura2008; klenow2008; eichenbaum2011; kehoe2015; anderson2017; bils2004","Sales account for a large share of price changes; regular prices are sticky; sales are informationally rigid","US scanner/BLS micro data; Canada and Quebec evidence is scarce","First high-frequency (≈7 h) posted-price evidence for Quebec grocery banners; documents a measurement artefact (store mixture) relevant to all scraped-price studies"5C4,"Posted-price dispersion is mostly within-store/relative and persistent across stores (morphology of dispersion)",empirical,"kaplan2015; kaplan2019; lach2002; sorensen2000","Most dispersion is relative-price dispersion across stores for the same good; store ranks are persistent","Transaction-based scanner panels; WP37 observes banners not stores","Quantifies cross-banner persistence of relative price gaps on exact-UPC pairs (Metro vs Super C) and brand+size pairs across companies"6C5,"Large retailers set near-uniform prices across stores of a chain (uniform/zone pricing)",empirical,"dellavigna2019; adams2024; hitsch2019; hitsch2021","US chains price nearly uniformly within chain; promotions are chain-wide events","If Quebec banners priced uniformly, the store-mixture oscillation would not appear; its presence is informative","Provides indirect evidence against full within-banner uniformity in Quebec online channels (price value sets of 3–5 levels per product-week)"7C6,"Online prices track offline prices closely for multi-channel retailers; scraped prices are valid for inflation measurement",empirical,"cavallo2017; cavallo2016; cavallo2018; gorodnichenko2017; cavallo2023","Online = offline for most items in 10 countries; scraped data show more frequent changes than CPI","Cavallo compares identical products in the same retailer; WP37 cannot observe offline prices","Shows that anonymous-session scraping of store-selected sites returns a mixture of store prices — a caveat for Billion-Prices-type collection"8C7,"Matched-model and multilateral indices (GEKS/Törnqvist, chained) avoid chain drift; naive average-price indices are biased by assortment and substitution",theory/empirical,"ivancic2011; dehaan2011; diewert2022; melser2018; feenstra1994; redding2020","Chain drift from sales; multilateral methods; variety and taste shock adjustments","Expenditure weights are unavailable in WP37 (listings only) — only unweighted/Jevons-type and fixed-basket indices can be built","Quantifies the gap between naive average listed price and matched-model indices on the same Quebec data; honest unweighted labelling"9C8,"Package downsizing (shrinkflation) is a hidden price increase; consumers are less sensitive to quantity than price",empirical,"gourville2004; cakir2014; cakir2021; hoppe2024","Downsizing raises unit price with muted demand response; pass-through to retail","Short 81-day window: few size changes are observable; detection relies on product-text size changes within a listing","Documents frequency of within-listing size-label changes and their unit-price impact over 11 weeks; explicit about low power"10C9,"Shopping effort and store choice lower paid prices; households could save substantially by buying the cheapest available",empirical,"aguiar2007; griffith2009; kaplan2016; nevo2019","Paid prices fall with shopping time; potential savings 10–30 % under hypothetical perfect shopping","Savings bounds require transaction data and store access; WP37 has posted prices and no geography","Computes unconstrained vs banner-count-constrained basket cost frontier on posted prices; labels it an upper bound; geography left to the prospective design"11C10,"Spatial access and assortment availability shape effective food prices",empirical,"allcott2019; handbury2015","Food deserts explained mainly by demand; prices vary across cities with availability","No store geography in Food-Ka","Not testable; stated as limitation with a prospective data plan (store-level circular zones)"12C11,"Menu costs and multi-product firms generate small and large price changes; sales are decoupled from macro shocks",theory,"golosov2007; midrigan2011; nakamura2013; guimaraes2011; coibion2015","Menu-cost models with sales; sales respond weakly to monetary policy","Not identifiable from 81 days","Descriptive size distribution of posted-price changes; no structural estimation claimed"13C12,"Private labels and brand premia are quality-adjusted price differences",empirical,"dube2018; bronnenberg2015","Private-label share rises in recessions; informed shoppers buy store brands","No quantities","Reports national-brand vs private-label unit-price gaps within categories and banners (descriptive)"14C13,"Retail competition (entry of Walmart, EDLP vs Hi-Lo) changes price levels and promotion intensity",empirical,"hausman2007; lal1997; hoch1994; ellickson2008","EDLP vs Hi-Lo strategies; Walmart lowers prices","No entry events in window","Characterises each banner's promotion intensity and price level on matched items (EDLP vs Hi-Lo typology for Quebec)"15C14,"Probabilistic record linkage requires validation (precision/recall) and is a source of measurement error",method,"fellegi1969; christen2012","Linkage theory and evaluation practice","—","Calibrates name-based linkage against UPC ground truth and reports tier-specific precision; propagates match uncertainty"16C15,"Canadian grocery retail is highly concentrated (Loblaw, Sobeys, Metro plus Walmart and Costco)",institutional,"competitionbureau2023","Market study: concentration, margins, need for more competition","Report, not peer-reviewed","Maps 54 feeds to companies/banners/channels, showing that apparent banner diversity collapses to few companies"17