In the summer of 1986, 564 of the 752 members of the treatment group of the first full-scale implementation of the Summer Training and Education Program (STEP) model returned for their second summer. At the same time, a second cohort consisting of 1,591 youth (765 in the treatment group and 754 in the control group) began their first summer of participation. STEP had substantively large effects on the Cohort II participants' reading and math skills, knowledge of contraception, and sexually related behavior during their first summer of participation. The effects of program participation on basic skills were larger and much more widespread than those for Cohort I's first summer (1985) and thus are more likely to result in the desired longer-term outcomes. The Cohort II control group youths experienced substantial learning losses in both reading and math over the 1986 summer, as had the Cohort I control group youth in the summer of 1985. The research also examined STEP's impact on the school-year (1985-1986) and second-summer (1986) performance of Cohort I youths. Those in the Cohort I treatment group were 22 percent less likely to fail a grade than were their counterparts in the control group. The impact was especially large for Hispanics. Other school-year effects from participation in STEP appeared to be small. (Appendixes include a program participation analysis, a description of the Summer Work Enhancement Program, technical data tables, tables referenced in the text, and figures on the total cost of STEP in 1986.) (MN)