The Comprehensive School Mathematics Program (CSMP) is a program of CEMREL, Inc., one of the national educational laboratories, and was funded by the National Institute of Education (NIE). Its major purpose is the development of curriculum materials for the elementary grades. Beginning in September 1973, CSMP ran an extended pilot trial of its elementary program. The material looks at the results of interviews carried out in the St. Louis area with nine CSMP and nine non-CSMP fourth-grade classes. Six students were selected from each class. The nine CSMP classes were veteran classes having used CSMP as their regular program since first grade. Six different problem exercises were administered to subjects. Results showed significantly higher scores for CSMP pupils than non-CSMP individuals on two of the exercises, some difference thought worth noting on one additional problem also favoring CSMP students, and small and not significant differences between groups on the other three measures. It is noted that boys in both CSMP and non-CSMP groups outperformed their female classmates. (MP)