Source: Jack Fiorito, Paul Jarley, Journal of Labor Research, Volume 33, Issue 4, December 2012
From the abstract:
This study analyzes U.S. union organizing activity and membership growth from 1990 to 2004, a period in which an overall pattern of union decline continued and in which organizing achieved renewed prominence as both a union policy and public policy issue. Models for organizing activity and membership growth were proposed and tested. Union decentralization and employer opposition were found to be key predictors of organizing activity differences among unions. These same factors, along with organizing activity, helped explain union differences in membership growth, as did a “Sweeney era” effect.