Scores on ETS-developed interim assessments were correlated with scores on the state of Nevada’s criterion-referenced test (CRT) for students in Grades 3, 5, and 8 in the Clark County (Nevada) School District. At each grade level, more than 12,000 students were assessed in reading and math on three interim assessments spread over the year and on the spring CRT. Across groups defined by gender, ethnicity, socioeconomic status, and English proficiency, patterns of means on the interim assessments matched the patterns on the CRT, and correlations were high and virtually equivalent in all subgroups.