Validity and Reliability Issues of Performance-Portfolio Assessment

In a time when alternative assessment techniques, such as portfolios, are becoming more accepted, there remain questions regarding validity and reliability of such assessments. The author evaluated the validity and reliability of performance-portfolios in a preservice elementary methods class. In order to examine the validity of performance-portfolios, the students' domain-strategic and general-learning strategic knowledge were assessed. These measures, along with the number of education courses and the total hours of prior teaching experience, were used to predict group membership of students as determined by performance-portfolio scores. The contribution of each predictor variable, the percent of correct predictions, and the canonical discriminant functions were examined. The reliability was examined by comparing the two course instructors' scoring to each other and to student peer-raters. Results support performance portfolios as a valid method of assessing desired abilities of preservice teachers that can be reliably graded.