he Retail Prices Index (RPI) is the most generally recognised yardstick used in the UK to measure the rate of inflation, which refers to the general increase in prices and fall in the purchasing power of money. The index takes into account most items that money is spent on and weights them together in a way that reflects their importance in a consumer's shopping basket. Frequently bought items like food attract a large weight while infrequent purchases such as durable goods are given a smaller one. The rise in the cost of the constituents of the shopping basket is presented as an index, and is calculated and published every month. Periodic adjustments of the mix of items in the basket are made to keep up with changes in expenditure patterns.