Dental clinical evaluation: a review of the research.

Preclinical and clinical evaluation in dental education needs systematic study. Research on the main variables affecting reliable and valid clinical evaluation is reviewed to identify research findings applicable to clinical evaluation settings. The research reviewed shows that performance criteria should be objectively stated, that measurement scales should contain few points, and that evaluator training may improve reliability. Suggestions for the design of future evaluation studies are provided in an effort to expand the scope and usefulness of this type of research.

Sample size needed for student ratings of instruction.

The number of evaluation forms students are asked to complete is multiplying. To reduce that number, the present study determines the minimum sample size needed for accurate student ratings of instruction. Typical questionnaire items using four- and seven-category ratings scales were studied. Data for four class sizes (40, 60, 100, 140) were sampled in graduated sizes, and a standard error of the mean was computed for each sample size. A permissible error index was computed to estimate the accuracy of ratings obtained from any sample size needed for the four different class sizes. Figures are presented from which minimum sample sizes necessary for accurate student evaluation of instruction can be computed. The figures show that sampling only one-third of classes of 100-140 students is sufficient to obtain accurate evaluations.