The Comprehensive Tests of Basic Skills (CTBS/S) was the nationally standardized, norm-referenced test selected for the Idaho Statewide Testing Program for 1976-77. It provided basic skills measures in reading, language, mathematics, total battery, reference skills, science and social studies. Students in the 4th, 8th and 11th grades from 51 of Idaho's 115 school districts were selected on a random basis for participation in the testing program. The sampling procedure provided a sample representative of the state's students both by geographic location and by size of school attended. Analysis of the data compared the mean (average) performance of Idaho students on the CTBS/S measures to the mean performance of the national norm group, and compared Idaho's upper and lower students to their counterparts in the national norm group. Out of the analysis came three major findings: (1) The mean performance of Idaho's students at the 4th, 8th and 11th grades was either equal to or better than the national norm on each of the 19 CTBS/S total scores for reading, language, mathematics, battery, reference skills, science and social studies. (2) On 4l of the 43 CTBS/S scores reported at the three grade levels, the mean performance of Idaho's students was either equal to or better than the national norm. The two exceptions were 4th grade spelling and 4th grade mathematics computation. (3) Idaho's lower achieving students in the 4th, 8th and 11th grades consistently performed better on the CTBS/S than their national counterpart, with the exception of 4th grade spelling and 4th grade mathematics computation. The relationship of Idaho's upper achieving students to their national counterpart varied from test to test and across the three grade levels. (RC)