The demonstration was based in part on the theory that both school completion and work experience greatly enhance the employment prospects of teenagers. Unlike previous youth employment programs, the YIEPP tied school and work together by offering jobs to all youths who met the eligibility criteria and also agreed to remain in or return to school. The demonstration began in February 1978 and ended full-scale operations in August 1980. During this time, over 76,000 youths were employed by YIEPP work sponsors at 17 project sites across the country, operated by competitively-selected CETA (Comprehensive Employment Training Act) prime sponsors. The demonstration showed that selected prime sponsors could feasibly enroll large numbers of economically disadvantaged youths in a guaranteed jobs program and provide them with adequate work experience despite demanding program constraints of time and scale. Disadvantaged youths, in turn, were very interested in working, even with the school condition, as evidenced by their high application and participation rates. In-school youths, however, were more attracted to the program than drop-outs, as were blacks more so than whites and younger youths more so than older ones. Less feasible was the enforcement of some of the eligibility and school performance standards. Although the requirement of school enrollment for participating youths was well-monitored, the school performance standards were more difficult to establish and enforce on an ongoing basis. Appendixes contain site profiles, supplemental tables and charts, and a methodological appendix for length of stay and termination analysis. Twenty-four references are provided. (Author summary modified)