Briefly presented are the rationale and procedures used to develop and validate an interactive videodisc program to assist in diagnosing difficulties in mathematics in grades 1-3. The mathematics assessment program is described as 408 criterion-referenced items divided into seven strands. Questions are administered until a student makes three consecutive errors; then the student is branched to the next section in a strand. At the teacher's option, the test can be administered in either English or Spanish. Information is also included on equipment configurations possible among videodisc players, microcomputers, touch screens, and printers, and disc capacity is noted. Finally, comments on formative evaluation needs are given. (MNS)