ERIC Number: ED371038
Record Type: RIE
Publication Date: 1994-Apr
Reference Count: N/A
Development of a Valid Subtest for Assessment of DIF/Bias.
By definition, differential item functioning (DIF) refers to unequal probabilities of a correct response to a test item by examinees from two groups when controlled for their ability differences. Simulation results are presented for an attempt to purify a test by separating out multidimensional items under the assumption that the intent of the test constructors was to construct a unidimensional test for a given population. The procedure used to arrive at the purified and essentially unidimensional subtest used the multidimensional theory of DIF/bias proposed by Shealy and Stout (1993) and the statistical procedure DIMTEST for assessing essential unidimensionality. When applicable, the proposed methodology leads to a statistically validated construct valid subtest that can be used in the matching criterion for DIF/bias analysis. This methodology can be applied to an internal or external matching criterion. It is only applicable when the majority of test items are tapping the intended ability for a given population, while a few items are tapping other major abilities in addition to the intended ability. This method is not applicable when DIF/bias is pervasive. Ten tables summarize analysis results. (Contains 28 references.) (SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A
Identifiers: DIMTEST (Computer Program); Multidimensionality (Tests); Purification (Statistics)
Note: Paper presented at the Annual Meeting of the American Educational Research Association (New Orleans, LA, April 4-8, 1994).