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 1973, CSMP ran an extended pilot trial of its elementary program. The 1976-77 period was the fourth year. This report describes results of three studies involving veteran CSMP third-grade classes, and covers between them 33 of the 88 veteran classes. Results indicate that CSMP students at the end of third grade appear to be developing satisfactory computational skill. At one of three sites, however, there was evidence that CSMP students did not do well on the concepts items of the Comprehensive Tests of Basic Skills (CTBS), particularly those dealing with sets and number sentences. (MP)