Employment Cost Index technical note
Last Modified Date: October 30, 2015
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
Data for the September 2015 reference period were collected from a probability sample of approximately
36,900 occupational observations selected from a sample of about 8,600 private industry establishments
and approximately 8,900 occupational observations selected from a sample of about 1,500 state and local
government establishments that provided data at the initial interview.
To assist users in ascertaining the reliability of Employment Cost Index (ECI) series, standard errors of
all current quarter estimates except seasonally adjusted series are made available shortly after publication
of the news release. Standard errors provide users a measure of the precision of an estimate to ensure that
it is within an acceptable range for their intended purpose. For further information see:
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 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). These releases are
issued 3 months after the reference period. The ECEC release dates are available at:
www.bls.gov/schedule/news_release/2015_sched.htm. 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.