C2ER calculates the Cost of Living Index (COLI) by measuring consumer expenditure amounts for the six major categories and creating weights or ratios for the amount each item contributes to the overall index. The Cost of Living Index Committee has adopted the weights based on data from the U.S. Bureau of Labor Statistics’ 2004 Consumer Expenditure Survey, using the data on the proportional distribution of expenditures by households in which the reference person has a professional or managerial occupation and by households in the upper quintile of income. For urban areas where there is less reported data, C2ER develops estimated prices in order to have a complete set of observations.

How does Lightcast COLI data differ from C2ER?

C2ER annually publishes the cost of living index at the county level for the entire US. C2ER also publishes a quarterly COLI for ~250 US MSAs, which Lightcast does not currently use. For geographies larger than a single county, Lightcast creates an index by using the averages of the comprised counties (the COLI is pre-weighted by each county's population). This way the index more appropriately represents the region's cost of living. Lightcast applies the county COLI from the county to the ZIPs within that county.