Curriculum bias and reading achievement test performance

The overlap of words specifically taught in reading textbooks with the contents of standardized reading achievement tests may be a source of bias that is frequently overlooked in psychoeducational assessments. This study compares the standardized achievement test performance of 62 second graders receiving instruction in two different reading curricula (Open Court and Houghton-Mifflin) to determine whether either curriculum generates different quantitative estimates of reading achievement. Reading subtest scores derived from the Kaufman Test of Educational Achievement-Brief Form (K-TEA), the Wide Range Achievement Test-Revised (WRAT-R), and the Reading Recognition and Reading Comprehension subtests from the Peabody Individual Achievement Test (PIAT) were examined. Grade level equivalents and scaled scores from the California Achievement Test (CAT) were also examined. Three Curriculum × Test repeated measures ANOVAs were conducted using grade level scores (2×7), standard scores (2×4), and CAT scaled scores (2 × 5) as dependent measures. A significant Curriculum × Test interaction was identified, suggesting differences among tests in estimates of reading ability as a function of the reading program.