Technical Adequacy of General Outcome Measures for Middle School Mathematics

This study examined three aspects of technical adequacy with respect to two general outcome measures in mathematics. The first two aspects were the effects of aggregating scores and correcting for random guessing on the reliability and validity of the measures. The third issue was the extent to which the measures were sensitive to changes in student performance. One hundred and five sixth-grade students completed two general outcome measures (basic facts and estimation) weekly for a 10-week period. With respect to aggregation, the results indicated that while fluency with basic facts is measured quite precisely with a single score, aggregation of scores for the estimation task increases both reliability and validity. Correcting the estimation scores for random guessing is recommended to increase criterion validity. Analyses of sensitivity to growth revealed that although both the fact and estimation measures reflect statistically significant changes across the 10-week period, the fact measure is likely to have greater practical significance. The article closes with a discussion of the relative merits of the measures for special education practice.