Our proposed research will investigate the causes of joblessness among older workers by studying how their prospects for reemployment respond to time unemployed, tightness of local labor markets, and differences in job history. The research will consist of an experimental, ?audit? study of differences in the call back rate of job applicants (ages 50 and older), by time unemployed. The basic approach of the experiment is to send out matched pairs of applications from workers to job openings. The two applications in a pair will be equivalent except for the time that the applicants had been unemployed. By sending out approximately 12,000 such pairs, with different durations of unemployment, in different labor markets, and with different job histories, and recording whether the applications receive a positive call back, we can estimate the relationship between the call back rate and duration unemployed, under different circumstances, for otherwise identical older applicants.