EN
Scanner data are electronic transaction data most often from retail chains and obtained from electronic retail terminals. The identification of products takes place after scanning their characteristic barcode (e.g. EAN or GTIN), thus in the case of scanner data, we have full product information (price, sales volume, weight, description, etc.) at the most disaggregated level. In the cases of many countries, as well as Poland, this type of data is a valuable alternative source of information when estimating inflation. This paper discusses the main advantages but also the challenges of using scanner data in the CPI measurement. The main purpose of the paper, however, is to discuss the problem of selecting an optimal price index formula that would be appropriate for the highly dynamic (in terms of product rotation) scanner data. The considerations, supported by examples of empirical studies, will be demonstrated using the PriceIndices package in the R environment.