A Comparison of the ANCILLES and LOGIST Parameter Estimation Procedures for the Three-Parameter Logistic Model Using Goodness of Fit as a Criterion.
Abstract
A study was conducted to compare the quality of the item parameter estimates obtained from the ANCILLES and LOGIST estimation procedures using goodness of fit as a criterion. Statistics used to compare the fit yielded by the procedures included a chi-square statistic and a mean square deviation statistic. Other analyses performed included comparisons of the distributions of the parameter estimates obtained from the procedures, and a set of meta-analyses performed on the chi-square statistics obtained for the items. The data for the study was composed of 50 items and 2,000 cases obtained using a stratified random sample of 357 items and 4,000 cases of the Iowa Tests of Educational Development. Results indicated that differences did exist in the quality of parameter estimates obtained from the ANCILLES and LOGIST procedures. More items for ANCILLES showed significant lack of fit than for LOGIST, based on the chi-square tests. However, a test to determine whether the ANCILLES chi-squares were longer than the LOGIST chi-squares significantly more than half the time was not significant. Also, the dependent t-computed for the MSD statistics was not significant. Further analyses indicated that the parameter estimates obtained from the two procedures were highly correlated. Comparisons of the item parameter estimates with the chi-square values indicated that ANCILLES yielded poor fit for items with extreme difficulty values. Because of this, and the fact that ANCILLES did not provide estimates for all the items, it was conducted that there were real differences in the quality of the parameter estimates obtained for the two procedures. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1980
- Accession Number
- ADA097081
Entities
People
- Mark D. Reckase
- Robert L. Mckinley