An overview and summary are presented of the implementation of the Connecticut Mastery Test for grade 4. The testing program assesses essential skills in mathematics and language arts including listening, reading, and writing for students in grades 4, 6, and 8. The criterion-referenced mastery test assesses how well each student is performing on skills identified by content experts and practicing educators as important for students entering the fourth grade. In 1991, fourth graders mastered an average 21.2 of the 25 mathematics objectives tested, representing no change from the preceding year. A total of 88.4 percent of the students scored at or above the remedial standard, slightly up from the preceding year. In language arts, there was no change from the preceding year, as fourth graders mastered an average of 6.3 of the 9 objectives tested. In writing, fourth graders averaged 4.9 on a scale of 2 to 8, slightly down from 1990, although the number scoring above the remedial standard increased somewhat. In reading, fourth graders averaged 49 units on the Degrees of Reading Power, up slightly from 1990. About 53 percent scored at or above the reading goal, an increase from 1990. Comparative information for 1985 through 1991 is given. Twelve charts present test results, and 12 appendixes provide supplemental information about testing and scoring. (SLD)