High-Frequency Food Prices: Evidence from the Czech Republic

Abstract

With increasing engagement in on-line shopping accelerated by the events of 2020, what can we learn about prices and their rigidity in the on-line sector? We collect an extensive dataset of scraped daily prices for four on-line grocery retailers from the Czech Republic from January 2020 to April 2021. We find substantial di erences in pricing among the retailers, including the impact of interest rate changes and the introduction of lockdowns on the probability of price change. Price rigidity depends significantly on the retailer and the assumptions imposed on temporary price changes. The mean number of all price changes among retailers ranges between 3.10 and almost 11 per year. Depending on the definition of excluded temporary price changes, retailers change prices permanently on average between 0.68 to 4.04 times per year. We show that a more in-depth analysis of temporary price changes is crucial for a robust assessment of price rigidity. JEL Classification E30, L81, C55, D22 Keywords on-line grocery shopping, price flexibility, tem- porary price changes, scraped prices Title High-Frequency Food Prices: Evidence from the Czech Republic

Co se m ûeme dozv d t o cenách v on-line sektoru s jeho rostoucím vyuûítím urychlen˝m událostmi roku 2020? Posbírali jsme rozsáhl˝ dataset scrapovan˝ch denních cen ty on-line obchod prodávajících potraviny v eské republice z období mezi lednem 2020 a dubnem 2021. Naöli jsme v˝razné rozdíly v cenotvorb mezi obchody, a to v etn vlivu zm n sazeb a zavedení lockdown na pravd podobnost zm ny ceny. Cenová rigidita siln závisí na obchodu a p edpokladech o do asn˝ch cenov˝ch zm nách. Pr m rn˝ po et vöech zm n ceny se mezi obchody pohybuje v intervalu od 3.10-ti do skoro 11-ti za rok. V závislosti na definici vynechan˝ch do asn˝ch cenov˝ch zm n m ní obchodníci permanentn ceny v pr m ru 0.68 aû 4.04-krát za rok. Ukazujeme, ûe podrob- n jöí anal˝za do asn˝ch cenov˝ch zm n je nezbytná pro robustní posouzení cenové rigidity. Klasifikace JEL E30, L81, C55, D22 Klí ová slova on-line nákupy jídla, cenová flexibilita, do asné cenové zm ny, scrapované ceny Název práce Ceny potravin ve vysoké frekvenci: evi- dence z eské republiky