Data from the first trial of the computer-based nationwide common achievement test in medicine, carried out from February through July in 2002, were analyzed to evaluate the applicability of the item-response theory. The trial test was designed to cover 6 areas of the core curriculum and included a total of 2791 items. For each area, 3 to 40 items were chosen randomly and administered to 5693 students in the fourth to sixth years; the responses of 5676 of these students were analyzed with specifically designed computer systems. Each student was presented with 100 items. The itemresponse patterns were analyzed with a 3-parameter logistic model (item discrimination, item difficulty, and guessing parameter). The main findings were: 1) Item difficulty and the percentage of correct answers were strongly correlated (r=-0.969to-0.982). 2) Item discrimination and the point-biserial correlation were moderately strongly correlated (r=0.304 to 0.511). 3) The estimated abilities and the percentage of correct answers were strongly correlated (r=0.810 to 0.945). 4) The mean ability increased with school year. 5) The correlation coefficients among the 6 curriculum area ability scores were less than 0.6. Because the nationwide common achievement test was designed to randomly present items to each student, the item-response theory can be used to adjust the differences among test sets. The first trial test was designed without considering the item-response theory, but the second trial test was administered with a design better suited for comparison. Results of an analysis of the second trial will be reported soon.

PURPOSE: . The aim of this study was to introduce rating criteria to evaluate student performance in a newly developed, digital wax-up preclinical program for computer-aided design (CAD) of full-coverage crowns and preliminarily investigate the reliability and internal consistency of the rating system. MATERIALS AND METHODS: . This study, conducted in 2017, enrolled 47 fifth-year dental students of Okayama University Dental School. Digital wax-up training included a fundamental practice using computer graphics (CG), multipurpose CAD software programs, and an advanced practice to execute a digital waxup of the right mandibular second molar (#47). Each student’s digital wax-up work (stereolithography data) was evaluated by two instructors using seven qualitative criteria. The total qualitative score (0-90) of the criteria was calculated.The total volumetric discrepancy between each student’s digital wax-up work and a reference prepared by an instructor was automatically measured by the CAD software. The inter-rater reliability of each criterion was analyzed using a weighted kappa index. The relationship between the total volume discrepancy and the total qualitative score was analyzed using Spearman’s correlation. RESULTS: . The weighted kappa values for the seven qualitative criteria ranged from 0.62 - 0.93. The total qualitative score and the total volumetric discrepancy were negatively correlated (ρ = -0.27, P = .09, respectively); however, this was not statistically significant. CONCLUSION . The established qualitative criteria to evaluate students’ work showed sufficiently high inter-rater reliability; however, the digitally measured volumetric discrepancy could not sufficiently predict the total qualitative score.