The Retail Price Index (RPI) is a measure that tracks changes in the average retail prices of a basket of goods and services over time. It is a widely used indicator to assess inflation and price trends in an economy. The RPI considers the prices of various items, including housing, transportation, food, and other everyday goods and services. Governments and economic analysts often use the RPI to gauge the impact of price changes on consumers and to make adjustments to policies such as pensions and wages. While the RPI has been historically used, some countries have transitioned to other indices like the Consumer Price Index (CPI) for more accurate inflation measurement.