Definition: Rolling survey approach
Purchasing power parities
The approach that allows PPPs (Purchasing power parities) to be calculated annually when, for cost reasons, price collection is cyclical and spread over a number of consecutive years. In other words, not all products in the basket being surveyed are priced every year. Prices for products that are not priced are rolled over from the year when they were last priced after being adjusted for any price change that has occurred in the meantime. PPPs for any given year are calculated with the prices that have been collected during the year and the prices that have been rolled over from consecutive years. Eurostat uses the approach for consumer goods and services and for construction. Price collection is spread over three years for consumer goods and services and over two years for construction.
Eurostat, Organization for Economic Cooperation and Development (OECD), "Eurostat-OECD Methodological Manual on Purchasing Power Parities", Publications Office of the European Union, Luxembourg, 2012