| Abstract: | This article considers two new smoothing methods in equipercentile equating , the cubic B-spline presmoothing method and the direct presmoothing method. Using a simulation study , these two methods are compared with established methods , the beta-4 method , the polynomial loglinear method , and the cubic spline postsmoothing method , under three sample sizes (300 , 1,000 , and 3,000) and for three test content areas (ITBS Maps and Diagrams , ITBS Reference and Materials , and ITBS Capitalization). Ten thousand random samples were simulated from population distributions , and the standard error , bias , and RMSE statistics were calculated. The cubic B-spline presmoothing method performed well in reducing total error of equating , whereas the direct presmoothing method appeared to need some modification for it to be as accurate as other smoothing methods. |
