Examines the relationship between ability and seniority in the context of the “pessimistic” theory – that the use of seniority as a factor in promotions impairs productivity and individual initiative. The author posits that more study is needed, but suggests that seniority might be favored over ability as a factor in reviewing promotional decisions not simply because unions are pressing for seniority, but also because seniority is easier to judge: arbitrators place the burden on management to justify selection of a junior employee, and management does not always do a good job of justifying its actions.