Dinâmica dos preços da cesta básica em Fortaleza: evidências de um estudo econométrico espacial

Abstract

This dissertation assesses the validity of the Law of One Price (LOP) in the intra-urban context of the city of Fortaleza, focusing on the prices of basic food basket items sold by supermarkets. Using fiscal microdata from 156 establishments collected between 2022 and 2024, the research investigates the extent to which local competition and geographic location influence the convergence of essential goods prices. To this end, a spatial autoregressive model with heterogeneous coefficients is applied, following recent developments in spatial econometrics. Initially, the results suggest price convergence among neighboring supermarkets, consistent with the assumptions of the LOP. However, after controlling for common factors that simultaneously affect all establishments, these effects become statistically insignificant, revealing a more heterogeneous price structure than suggested by the raw data. The analysis by supermarket chain indicates distinct behaviors among groups, suggesting that commercial strategies and local socioeconomic characteristics shape competitive dynamics. Although a broad pattern of competitive convergence is not identified, localized effects point to strategic adjustments in specific market contexts. The findings contribute to the debate on price integration in urban environments and offer empirical evidence relevant to regulation and competition policies. By revealing limitations of the LOP at reduced spatial scales, the study enhances the understanding of market dynamics in cities with heterogeneous commercial structures, reinforcing the importance of granular data in the formulation of monitoring and policy strategies.