The setting for this study was a basic education component of a summer youth program designed to increase chances of high risk adolescents, mostly minorities, whose ages ranged from 14-18, to experience more positive academic and employment outcomes. The instructional program used in both experimental and control classrooms emphasized mastery learning of a selected set of mathematics and reading/language arts objectives. Pretests and posttests based on the objectives were developed using the Academic Instructional Measurement System. Of the four sites used, only one was the experimental site where the mastery learning program was implemented using the microcomputer. Quantitative assessment of the experimental program was provided by comparing the effect sizes of the experimental group with the effect sizes of the remaining three sites. Observations were made of the instruction given in the experimental classroom as well as one of the other program sites. The results provide additional evidence of the effectiveness of mastery learning techniques with high risk and minority students. Students at each location made sizeable gains in both mathematics and reading/language arts during a fairly short time period. Although the quantitative results did not show the computer setting to be more effective than the non-computer setting, the qualitative analyses of these two settings revealed educational benefits for high risk students in the computer environment that may not be reflected in a measure of academic achievement. These students demonstrated an increased sense of social integration and bonding, factors that may help to reduce dropout. (16 references) (GL)