Revision of a Criterion-Referenced Vocabulary Test Using Generalizability Theory

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Takaaki Kumazawa



Classical test theory (CTT) has been widely used to estimate the reliability of measurements. Generalizability theory (G theory), an extension of CTT, is a powerful statistical procedure, particularly useful for performance testing, because it enables estimating the percentages of persons variance and multiple sources of error variance. This study focuses on a generalizability study (G study) conducted to investigate such variance components for a paper-pencil multiple-choice vocabulary test used as a diagnostic pretest. Further, a decision study (D study) was conducted to compute the generalizability coefficient (G coefficient) for absolute decisions. The results of the G and D studies indicated that 46% of the total variance was due to the items effect; further, the G coefficient for absolute decisions was low.