This study was undertaken to determine whether students who had received less adequate instruction and were less able in scholastic aptitude test performance than the subjects in previous studies might benefit more from special instruction. Specially prepared linear programed materials were developed in the verbal and the mathematical areas. Instruction in either of the two areas was given to eleventh grade students in predominantly Negro high schools. Alternate forms of the PSAT, administered as pre-and posttests, were used to evaluate the effectiveness of the special instruction. While there were statistically significant differences in gain scores between some of the experimental groups and their controls, the outcome of this study was generally negative. The gains in the experimental groups were more than offset by reductions in posttest scores in the control groups. The magnitude of the gains observed in the experimental groups were so small that it does not seem reasonable to expect that similar short-term instruction given on a wide scale would be of significant benefit to disadvantaged students. (Author/AG)