The TFP is one of four USDA-designed food plans specifying foods and amounts of foods to provide adequate nutrition. It is used as the basis for designing food stamp program benefits. It is the cheapest food plan and is priced monthly using the price data collected for the consumer price index (CPI). However, it is not the same as the food components of the CPI. The monthly cost of the TFP used for the food stamp program represents a national average of prices (four-person household consisting of an adult couple and two school-age children) adjusted for other household sizes through the use of a formula reflecting economies of scale. For food stamp purposes, the TFP as priced each June sets maximum benefit levels for the fiscal year beginning the following October.