ERIC Number: ED235190
Record Type: RIE
Publication Date: 1983-Apr
Reference Count: 0
An Assessment of the Relationship between the Assumption of Unidimensionality and the Quality of IRT True-Score Equating.
Cook, Linda L.; And Others
The purpose of this study was to empirically examine the relationship between violations of the assumption of unidimensionality, as assessed by the factor analysis of item parcel data, and the quality of item response theory (IRT) true-score equating, as measured by score scale stability. The verbal section of the Scholastic Aptitude Test (SAT) and the College Board Mathematics Level II examination were selected for use. Factor analyses were performed on each of the six selected test forms, using a correlation matrix of item parcel scores as input. The results of the factor analyses were related to the results of previous equating studies, hypothesizing that the equating chain that resulted in the least scale stability (SAT-verbal) would show evidence of greater multidimensionality than the equating chain (Mathematics Level II) that provided the superior equating results. The Mathematics Level II equating results were superior to the SAT-verbal equating results, and the dimensionality analyses revealed that the Mathematics Level II item parcels were more nearly unidimensional than the SAT-verbal item parcels. The dimensionality analyses also verified that SAT-verbal Form V4 and Mathematics Level II Form CC were each less parallel to the other two forms in their respective equating chains than the other forms were to each other. (BW)
Publication Type: Speeches/Meeting Papers; Reports - Research
Education Level: N/A
Authoring Institution: N/A
Identifiers: College Board Achievement Tests; Scholastic Aptitude Test; Unidimensionality (Tests); Violation of Assumptions
Note: Paper presented at the Annual Meeting of the American Educational Research Association (67th, Montreal, Quebec, April 11-15, 1983).