Fight Over the U.S. Labor Movement

 Hands in Solidarity, Hands of Freedom mural on the side of the United Electrical Workers trade union building on West Monroe Street at Ashland Avenue in Chicago, Illinois. Artist Dan Manrique Arias painted this mural in 1997 on the south wall of the United Electrical Workers Union.Hands in Solidarity, Hands of Freedom mural on the side of the United Electrical Workers union building in Chicago, Illinois. Painted by artist Daniel Manrique Arias in 1997 as part of the cross-border solidarity work between the UE and the FAT.      Photo credit: Chicago Public Art Group Photo Archives.

Welcome to the data repository for Union Booms and Busts: The On-Going Fight Over the U.S. Labor Movement.

Our book examines the shifting fortunes of U.S. workers and their unions on the one hand, and employers and their organizations on the other. Which factors helped and which hindered workers in their attempts to build unions in different industries? What lessons do these struggles offer for today's unions?

We analyze union power in 11 different industries over 115 years, including information on union membership and density, strikes, NLRB elections, decertification elections, Unfair Labor Practices, employment, occupation, race, and gender. We also collected yearly union membership numbers for all unions with collective bargaining agreements in more than one state.

This data was collected by us, Judy Stepan-Norris and Jasmine Kerrissey, with substantial help from Caleb Southworth in the earlier years of the study as well as from numerous research assistants. The data comes from various archives, government data sets,  union reports, and other sources. Early funding for this project was generously provided by the National Science Foundation (grant to Southworth and Stepan-Norris, and dissertation grant to Kerrissey), the University of California, Irvine Academic Senate and administration, and UCI’s Center for the Study of Democracy.

The careful reader will notice that sometimes memberships, elections, strikes, or labor force numbers fall or rise dramatically. We checked for accuracy in these cases, seeking to identify special circumstances to explain the shifts. We also encountered situations where different sources reported (usually slightly) different data. In those cases, we selected the information from the source we considered most valid and reliable. These decisions are documented in the book. We made every effort to ensure that all of the data we present is accurate, yet with the large volume we collected and coded, it is likely that some errors exist. If you identify an error, please report it to us (email 

We invite you to use this data to answer questions and to inform strategic decisions. We also welcome scholars and students to use it for research. When doing so, please cite Union Booms and Busts: The On-Going Fight Over the U.S. Labor Movement, Data Repository Table (or Graph) X.X.

To purchase the book at 30% off, use code: ASFLYQ6.


Data Repository


Yearly strike data include the number of strikes and the number workers involved in strikes at both the aggregate and industry levels.

Access/download dataset: Aggregate | Industry



These data showcase union elections through the National Labor Relations Board (NLRB), including yearly number of elections and results by result (won/lost) at the aggregrate and industry levels.

Access/download dataset: Aggregate | Industry



Charts feature the total number of union decertifications through the National Labor Relations Board (NLRB).

Access/download datset

Unfair Labor Practices (ULPs)

These data report the number of ULP cases filed by unions and employers. 

Access/download dataset


Union Membership

These data report the number of union membership by industry.

Access/download dataset


Union Density

These data depict union density by industry.

Access/download dataset


Census data show occupation and race and gender demographics by industry.

Individual Unions

These data report the yeary number of members in each union.

Access/download dataset



Works in Progress

Work in Progress: Union Genealogies

More to come soon from The Fight Over the U.S. Labor Movement project



Methodological Appendix


Overview of data collection methods and sources used for complete data repository.