Cost of living index data is available from online sources including the websites for the Census, the Council for Community and Economic Research and the Bureau of Labor Statistics. The Census advises that no official national cost of living index exists, but instead cites data from the other two sources.
The dataset that is called the Cost of Living Index is published by the Council for Community and Economic Research. The Census Bureau refers to this dataset in its 2012 Statistical Abstract. Cost of Living Index data is derived from the Census Bureau's county-level cost of living data and compares prices for expenses such as groceries and utilities between states and nationwide based on the county data. The extrapolated cost of living index is a privately produced data product and is available for a fee in several formats.
The Bureau of Labor Statistics publishes a similar dataset called the Consumer Price Index. The CPI is the most widely used measure of inflation. It is the official statistic used when calculating changes to Social Security payments, food stamp benefits and income tax brackets. The index is updated monthly and is available in subsets such as geographic regions, population groups and expenditure classes. The CPI compares prices on a wide range of expenses including groceries, rent and medical care. The BLS advises that the CPI is not a complete cost of living index even though it is often described that way.