Properties of Rasch residual fit statistics.
This paper examines the residual-based fit statistics commonly used in Rasch measurement. In particular, the paper analytically examines some of the theoretical properties of the residual-based fit statistics with a view to establishing the inferences that can be made using these fit statistics. More specifically, the relationships between the distributional properties of the fit statistics and sample size are discussed; some research that erroneously concludes that residual-based fit statistics are unstable is reviewed; and finally, it is analytically illustrated that, for dichotomous items, residual-based fit statistics provide a measure of the relative slope of empirical item characteristic curves. With a clear understanding of the theoretical properties of the fit statistics, the use and limitations of these statistics can be placed in the right light.
P. O. Box 3011, Strathmore, VIC 3041, Australia, wu@edmeasurement.com.au.
Margaret
M
Wu
Richard J
RJ
Adams
D000465:Algorithms; D003625:Data Collection; D003627:Data Interpretation, Statistical; D015233:Models, Statistical; D011594:Psychometrics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires