The Relationships Between the Iowa Test of Basic Skills and the Washington Assessment of Student Learning in the State of Washington

Executive Summary

Since 1993 educational reform efforts in the state of Washington have focused on three broad areas—the identification of Essential Academic Learning Requirements (EALRs), new student assessments of those requirements, and accountability. Extensive work in this second area has resulted in the Washington Assessment of Student Learning (WASL) given in the fourth, seventh, and tenth grades. These assessments are closely tied to the EALRs, and the results of these tests have become increasingly important to educators, policymakers and the public. At the same time, schools are also required to administer the Iowa Test of Basic Skills (ITBS) in third and sixth grades. Given the very different nature of the WASL and ITBS, questions have arisen regarding the relationship of student performance on the two assessments and the degree to which the assessments are complementary.

In Technical Report # 2 from the Washington School Research Center, professors Joireman and Abbott present a series of analyses that focus on these questions. Their primary sample is based on over 45,000 students who completed the third grade ITBS in 1999 and then completed the fourth grade WASL in 2000. Identical analyses are run on a second sample of over 16,000 students who completed the fourth grade WASL in 1998 and then completed the sixth grade ITBS two years later in 2000. “Will students who score high on the ITBS score high on the WASL, and vice versa? . . . the general answer is yes. . . . Students who score high on the ITBS Reading, Math, and Language Tests are likely to score high on the WASL Reading, Math and Writing tests. However, the sizes of these correlations are not so high as to conclude that the ITBS and WASL provide an identical assessment of student learning.”

Going beyond these general findings, Joireman and Abbott examine the different subtests within the ITBS and WASL, which “provides further support for the claim that the two tests assess similar, but not identical, abilities.” They find: “In sum, the ITBS and WASL are most similar in the major domains of Math and Reading, and are less strongly related in the remaining domains [listening, writing, language], and in terms of the subtests within each major domain.”

Finally, a statistical procedure called factor analysis is used to determine “whether reading and math on the ITBS and WASL are distinct or related learning domains.” The results suggest that reading and math on the WASL are more distinguishable than on the ITBS.

These analyses provide important information for Washington educators. The moderate correlations suggest that each test covers learning domains not covered in the other, thus being complementary. The moderate correlations also suggest that there is significant overlap between the instruments and that students (and therefore schools) who do well on one of the tests will tend to also do well on the other test. The combination of the two tests provides a more comprehensive picture of student achievement than does either of the tests individually. The results also suggest that success on the WASL Math assessment is less dependent on reading and language skills than is success on the ITBS Math assessment.

The data analyses in this report focus only on the elementary grades and do not provide the final answers to questions about the compatibility of the WASL and ITBS for learning assessments. On-going yearly analysis of the tests scores is important and should be extended to the upper grades. Nonetheless, the information contained in this report suggests that while the elementary level WASL and ITBS measure some of the same skills, each provides unique information on student achievement.

Jeffrey T. Fouts Executive Director
Washington School Research Center

full report (PDF Download)

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