This study develops and tests a model of union effects on staffing pra
ctices. Unionism is found to be associated with fewer recruitment sour
ces-suggesting that unionism reduces the need to increase applicant su
pply. Some data suggest that unionization increases the use of formal
selection methods-consistent with arguments that higher costs make it
important that the best applicants be selected. Other data support the
idea that unions resist selection practices that break down the colle
ctive identity among workers.