Employment Cost Index technical note

                                          TECHNICAL NOTE

The Employment Cost Index (ECI) measures the change in the cost of labor, free from the influence of 
employment shifts among occupations and industries. Detailed information on survey concepts, 
coverage, methods, nonresponse adjustment, and imputation can be found in BLS Handbook of Methods,
Chapter 8, “National Compensation Measures,” Bureau of Labor Statistics, on the Internet at 

Sample size

Data for the December 2014 reference period were collected from a probability sample of approximately 
37,700 occupational observations selected from a sample of about 8,700 private industry establishments 
and approximately 9,000 occupational observations selected from a sample of about 1,500 state and 
local government establishments that provided data at the initial interview.

Health insurance data

Data from the ECI that provide 12-month percent changes in employer costs for health insurance in 
private industry are available at www.bls.gov/web/eci/echealth.pdf.

Historical listings

Historical listings that provide all ECI data are available at www.bls.gov/ect/#tables. Included among 
these listings is one that provides continuous occupational and industry series. This listing uses the 
Standard Industrial Classification Manual and Census of Population series through 2005 and the North 
American Industry Classification System and Standard Occupational Classification from 2006 to the 
present. It provides the official series from the beginning of the ECI in 1975 through the current quarter. 
For more information on the criteria used in defining continuous series, see the article published in the 
Monthly Labor Review at www.bls.gov/opub/mlr/2006/04/art2full.pdf.

Employer Costs for Employee Compensation data

The costs per hour worked of compensation components, based on data from the ECI, are published in a 
separate news release titled "Employer Costs for Employee Compensation" (ECEC). The next ECEC 
release is scheduled for 10:00 a.m. (EDT), Wednesday, March 11, 2015. Historical ECEC data are 
available in summary documents at www.bls.gov/ect/#tables. Since the ECEC is calculated with current 
employment weights rather than the fixed weights used in computing the ECI, year-to-year changes in 
the cost levels usually differ from those in the ECI.

Updated employment weights and methodology changes

Fixed employment weights are used each quarter to calculate aggregate indexes for civilian, private, and 
state and local government. These fixed weights are also used to derive all of the industry and 
occupation series indexes. Beginning in December 2013, the 2012 employment counts from the 
Bureau’s Occupational Employment Statistics were used. Additional methodology changes include a 
partial implementation of the new NCS national sample design and adjustments to aggregate seasonally 
adjusted series. For more information, please contact the National Compensation Survey at 
202-691-6199 or ncsinfo@bls.gov.

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Last Modified Date: January 30, 2015