Work Stoppages technical note



                                            TECHNICAL NOTE


The major work stoppages series dates back to 1947. The term “major work stoppage” includes both 
worker-initiated strikes and employer-initiated lockouts that involve 1,000 workers or more and lasting at 
least one shift. BLS does not distinguish between lockouts and strikes in this publication.

Information on work stoppages is obtained from reports from the Federal Mediation and Conciliation 
Service, state labor market information offices, BLS Strike Report from the Office of Employment and 
Unemployment Statistics, and from media sources. One or both parties involved in the work stoppage 
(employer or union) is contacted to verify the duration and number of workers idled by the stoppage. 

Days of idleness is calculated by multiplying the number of workers involved in the strike or lockout by 
the number of days workers are off the job. The number of lost workdays for every major work stoppage 
is based on a 5-day workweek (Monday through Friday), excluding federal holidays.  

Monthly major work stoppages data

The Bureau of Labor Statistics compiles detailed monthly statistics on major work stoppages at 
www.bls.gov/wsp.  

Monthly time series data since 1981 have been published (data.bls.gov/cgi-bin/surveymost?ws) for the 
following tables:

   *   Number of work stoppages involving 1,000 workers or more beginning in the period
   *   Number of work stoppages involving 1,000 workers or more in effect in the period
   *   Number of workers involved in work stoppages beginning in the period
   *   Number of workers involved in work stoppages in effect in the period
   *   Days of idleness resulting from work stoppages in effect in the period
   *   Days of idleness resulting from work stoppages in effect in the period, as a percent 
       of estimated working time

Detailed historical major work stoppages data

Detailed data for each major work stoppage since 1993 are available at 
www.bls.gov/wsp/monthly_listing.htm. The major work stoppages historical data file includes the 
organization involved, location, beginning and ending work stoppage dates, the number of workers, and 
total days idle.

Major work stoppages detailed information and measures

For more information on Work Stoppages methods and measures, see “Chapter 8. National 
Compensation Measures” of the BLS Handbook of Methods at: www.bls.gov/opub/hom/pdf/homch8.pdf.

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Last Modified Date: February 10, 2016