A study assessed the costs and benefits of learning and of developing part-time employment of in-school youth. During the study, data were collected from a sample of 531 tenth- and eleventh-grade students drawn from an initial pool of 3,100 youngsters attending high schools in Orange County, California. To gather these data, researchers used survey questionnaires, on-site interviews of the adolescents, and interviews with their parents. The research design included both cross-sectional and longitudinal components. Researchers concluded that adolescents who take part-time jobs while in school experience a number of benefits, including development of personal responsibility and acquisition of knowledge about business and consumer matters. However, some of the benefits of working while in school have been overstated. Youngsters who work show no significant changes in their long-term educational or occupational plans. In addition, working entails costs. It can diminish involvement in school activities, is associated with increased absenteeism, and, in some cases, leads to a decline in school performance. Recommendations called for limiting student work to 15 to 20 hours per week, for encouraging youth to take jobs that provide opportunities for learning and contact with adults, and for closer collaboration among educators and employers. (MN)