Relatively little is known about how unions affect employers because of a lack of data and research at the level of the firm. The little evidence available suggests that the effects are complex and go well beyond the effects associated with higher wages. In particular, a better understanding of the role that unions play in providing training and greater attachment to the employer is needed. To the extent that public policy decisions make it more difficult for unions to organize employees, they reduce the competition that nonunion employers feel and reduce the incentives for these firms to maintain good human resource practices. Public policy decisions that make it more difficult for unions that provide extensive training, such as in the skilled trades, to retain their members may eventually make it impossible for those unions to provide training because they will be unable to recoup the costs through dues. Recommendations include (1) research at the firm level that will investigate the mechanisms through which union coverage affects the management of workers and the behavior of the organization as a whole; (2) consideration of costs in policy decision making; (3) unions as active partners in government training programs, especially for displaced workers; (4) where unions represent occupations where skills are general and employers therefore have no incentive to provide training, encouragement of union participation in training and more government training grants for that purpose. (51 references) (CML)