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The Internal Construct Validity of the SAT SAT

Dorans, Neil J.; Lawrence, Ida M.
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Factor Analysis, Scholastic Aptitude Test (SAT), TESTFACT, Test Validity


The primary goal of this research was to obtain a fuller understanding of what is being measured by the SAT. In addition, this project had two secondary goals: (1) the identification of a set of analytic techniques that can satisfactorily assess the dimensionality of the SAT; and (2) the identification of components of a cost-effective and informative system for monitoring the internal construct validity of the SAT. The principal project findings are: 1) The SAT-Mathematical test is effectively unidimensional. 2) The SAT-Verbal test is composed of two distinct albeit highly-related dimensions, a reading dimension and a vocabulary dimension; hence, there is an empirical justification for reporting two separate subscores. Currently, antonym and analogy items count toward a vocabulary subscore; sentence completion and reading comprehension items count toward a reading subscore. However, empirical data indicate that the sentence completion items appear to belong more with the analogy and antonym items than with the reading comprehension items. 3) This research points in the direction of using more reading passage items to achieve a more distinct and reliable reading subscore, using more sentence completion items because they are more reliable and may take less time than other items, and using fewer analogy items because they are less reliable and probably more time consuming than sentence completions or antonyms. 4) The analyses conducted in this study have served to underscore the value of using confirmatory factor analysis of item parcel data to study the dimensional structure of test data. This approach is computationally inexpensive, and appears to provide meaningful and consistent results. 5) Full information factor analysis is not ready for routine use with ATP data. The TESTFACT program is very expensive and sometimes yields "methodological" factors under the full information mode. The TESTFACT program can also produce a least squares factor analysis of a smoothed positive definite matrix of tetrachories corrected for guessing at a fraction of the cost of the full information solution. Unfortunately, this solution appeared to yield difficulty factors for both SAT-Verbal and SAT-Mathematical. (171pp.)

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