Changes in the union wage premium by industry

Relying on CPS data, the authors estimate the union wage premium-the amount by which wages of union workers exceeded those of nonunion workers in the same industry conditional on worker characteristics-for 32 industries over the period 1971-99. The dispersion of union premiums across industries narrowed over time as high premiums tended to fall and low premiums to rise. At the aggregate level, the premium drifted lower. When the authors model the union premium as a function of cyclical and structural variables and unmeasured industry characteristics, they find that Cost-of-Living-Adjustment (COLA) clauses reduced the responsiveness of the union premium to economic conditions and that increases in import penetration were strongly associated with rising union premiums. The effect of deregulation was mixed.