U.S. Bureau of Labor Statistics
Work Stoppages technical note
Last Modified Date: February 10, 2016
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
Monthly time series data since 1981 have been published (data.bls.gov/cgi-bin/surveymost?ws) for the
* 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.