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,” at www.bls.gov/opub/hom/pdf/homch8.pdf.

Sample size

Data for the September 2016 reference period were collected from a probability sample of approximately
28,400 occupational observations selected from a sample of about 6,800 private industry establishments 
and approximately 8,800 occupational observations selected from a sample of about 1,500 state and local 
government establishments that provided data at the initial interview.

Standard Errors

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: www.bls.gov/ncs/ect/ectvar.htm. 

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). These releases are 
issued 3 months after the reference period. The ECEC release dates are available at: 
www.bls.gov/schedule/2016/home.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. For additional information on the use of fixed employment weights in computing the 
ECI, see www.bls.gov/opub/mlr/2016/article/introducing-2012-fixed-employment-weights-for-the-
employment-cost-index.htm.  

Table of Contents

Last Modified Date: October 28, 2016