This award will enable Professor Anne C. Petersen, Department of Individual and Family Studies, The Pennsylvania State University, to collaborate with Professor Rainer K. Silbereisen, University of Giessen, Federal Republic of Germany. They will study the role of challenges in developmental transitions for producing problem behavior among some adolescents. Some challenges that have been implicated are early pubertal maturation, a school change in early adolescence, and expectations of limited schooling and adult work opportunities. Professor Petersen has carried out longitudinal studies on two samples of adolescents in the United States, one of middle to upper middle class adolescents, the other of lower to lower middle class adolescents. Professor Silbereisen has been doing similar research, using larger German and Polish samples. By combining their efforts the researchers will be able to examine a broader range of information on their variables of interest, and they will be able to test causal models of the processes by which some young people develop problems. Because of differences in the societies included in the collaborative research, such variables as schooling schedules, times and structures for entering the workforce, and expectations about when to start a family can be examined and included in the hypotheses.