Seniority establishes a clear and no ndiscretionary system by which participating employers must implement layoffs, schedule vacation time, assign shifts, and promote employees. Normally, an employee accrues seniority commensurate with her tenure of employment with her current employer. Seniority may be conditioned on the employee's job performance, and is not transferable from one employer to another. Federal law provides that seniority continues to accrue while an employee takes up to five years of unpaid military leave.
Employment security was one of the early goals of labor unions. In the late nineteenth and early twentieth centuries, unions sought to prevent employers from replacing older, higher paid workers with younger, lower-paid ones. Seniority provisions are thus a hallmark of union collective bargaining agreements. However, many employers of nonunion workers also have adopted seniority systems, particularly for implementing layoffs. In 1934, the automobile industry introduced seniority in layoffs a few years before its workers became unionized.
In the late twentieth and early twenty-first centuries workers experienced relatively greater job turnover (both voluntary and involuntary) that made seniority rules less significant. Moreover, seniority systems sometimes conflicted with other societal goals, such as racial equality or disability rights. In 1979, the Supreme Court in United Steelworkers of America v. Weber permitted private sector employers to implement race-based affirmative action programs, which supersede seniority systems by promoting some minority employees ahead of more senior white employees. In 2002, however, the Supreme Court in U.S.Airways Inc. v. Barnett held that employers need not supersede their seniority systems to accommodate disabled employees. Thus, a laborer who becomes disabled while working need not be given priority to obtain a sedentary "desk job" over a more senior non-disabled employee.
Bibliography
Brody, David. "Workplace Contractualism." In Industrial Democracy in America, edited by Nelson Lichtenstein and Howell John Harris. New York: Cambridge University Press, 1993.
