ITEM FUNCTION CHARACTERISTICS AND DIMENSIONALITY FOR ALTERNATIVE RESPONSE FORMATS IN MATHEMATICS

The purpose of this study was to investigate the technical properties of stem-equivalent mathematics items differing only with respect to re sponse format. Using socioeconomic factors to define the strata, a pro portional stratified random sample of 1,366 Connecticut sixth-grade st udents were administered one of three forms. Classical item analysis, dimensionality assessment, item response theory goodness-of-fit, and a n item bias analysis were conducted. Analysis of variance and confirma tory factor analysis were used to examine the functioning of the items presented in the three different formats. It was found that, after eq uating forms, the constructed-response formats were somewhat more diff icult than the multiple-choice format. However, there was no significa nt difference across formats with respect to item discrimination. A di fferential item functioning (DIF) analysis was conducted using both th e Mantel-Haenszel procedure and the comparison of the item characteris tic curves. The DIF analysis indicated that the presence of bias was n ot greatly affected by item format; that is, items biased in one forma t tended to be biased in a similar manner when presented in a differen t format, and unbiased items tended to remain so regardless of format.