Measuring association populations using the Encyclopedia of Associations: Evidence from the field of labor unions

Identifying populations of organizations has been a significant methodological challenge for scholars interested in examining various organizational dynamics. A common solution has been to rely upon a prior list or database of organizations. One such database on voluntary national organizations is the Encyclopedia of Associations (EA), a standard tool for sociologists and political scientists interested in associations. This paper compares coverage of labor unions as listed in the EA with information on the same universe of organizations taken from the US Department of Labor’s Office of Labor-Management Standards (OLMS). Results indicate that 103 of 135 (76%) of unions listed in the DOL were also listed in the EA. Among unions with more than 5000 members, EA coverage was 91%. Coverage rose to 95% among those unions with more than 10,000 members. Finally, two measures of financial size show the vast majority of unions with either receipts or net assets greater than $1,000,000 are included in the EA. The EA is therefore quite complete in coverage overall and appears to be nearly universal in its coverage of unions above even quite modest thresholds of organizational size and resources.