Abstract

Market Price Index
The change in food prices is one of the most fundamental economic indicators directly affecting the lives of households. Accurate and timely measurement of food inflation, one of the highest weighted components in the inflation basket, is crucial for effective policy design and the reliability of economic analyses, and is critical not only for economists and policy makers but also for broad segments of society. This study examines the role of daily frequency market data, which is a novel data source for Türkiye, in measuring daily food inflation compared to traditional price indices, and introduces the Market Price Index. The dataset, which consists of approximately 60 million daily observations from seven leading supermarkets with high market power in Türkiye, starting from June 2024, reflects instantaneous changes in retail food prices in great detail and enables real time monitoring of price fluctuations. Products have been classified according to their names using artificial intelligence techniques at the 5-digit level based on the European Classification of Individual Consumption by Purpose (ECOICOP), enabling the production of indices at the product group level. Price changes have been weighted using the turnovers obtained from the balance sheets of the supermarkets covered by the dataset, ensuring a highly representative measurement of inflation. The Food and Non-Alcoholic Beverages index has been constructed by weighting the indices computed at the level of 36 distinct product groups with the official Consumer Price Index weights. This process not only offers the opportunity for daily and more detailed analysis compared to traditional methods but also allows for a more timely measurement of food inflation than the official data published by TURKSTAT. According to the findings of the study, in 2025, the average monthly change of the Market Price Index was 1.9%, while the average monthly food inflation according to TURKSTAT was 2.1%. The mean absolute error (MAE) of the Market Price Index monthly changes was measured at 0.68.
Overall market data provides a high-frequency data source and offers significant benefits by allowing food inflation to be tracked at a daily frequency. The Market Price Index, produced within the Central Bank of the Republic of Türkiye, aims to support data-driven policy decisions through the analysis of high-frequency market data using modern statistical methods. It is expected that this approach will provide an innovative framework for measuring food inflation and support more effective and timely decision-making processes for policymakers regarding price stability.