This report presents evaluation results of the Home Instruction Program for Preschool Youngsters (HIPPY), carried out in Jerusalem, Israel. This experimental program was designed to improve the cognitive skills of children (4-7 years old) whose mothers had little formal schooling, and provides instruction in Hebrew and mathematics by using a set of structured learning materials under the supervision of family members. Progression in school and achievement data of 412 program participants (206 sibling pairs) in six locations were compared with similar data for a control group on non-participants. The results (taken for grades 1 and 2) were analyzed both by sibling pair and for differences between siblings. It was found that participants (1) were more likely to progress in a normative fashion through school, and (2) had somewhat higher achievement test scores in Hebrew reading and mathematics than non-participants. (GC)