This brief considers the problem of using value-added scores to compare teachers who work in different schools. The author focuses on whether such comparisons can be regarded as fair, or, in statistical language, "unbiased." An unbiased measure does not systematically favor teachers because of the backgrounds of the students they are…

This paper considers the model of school effectiveness (SE) currently dominant in research, policy and practice in England (although the concerns it raises are international). It shows, principally through consideration of initial and propagated error, that SE results cannot be relied upon. By considering the residual difference between the…

Under the assumption of normalcy, a formula is derived for the reliability of the maximum score. It is shown that the maximum score is more reliable than each of the single observations but less reliable than their composite score. (Author/LMO)

Prior standardization of scores when an aggregate score is formed has been criticized. This article presents a demonstration of the effects of differential weighting of aggregate components that clarifies the need for prior standardization. The role of standardization in statistics and the use of aggregate scores in research are discussed.…

Methods of estimating the standard error at different ability levels were compared. Overall, it was found that at a given ability level the standard errors calculated using different formulas are not appreciably different. Further, for most situations the traditional method of calculating a standard error probably provides sufficient precision.…

Multiple matrix sampling of three subscales of the California Psychological Inventory was used to investigate the effects of four variables on error estimates of the mean (EEM) and variance (EEV). The four variables were examinee population size (600, 450, 300, 150, 100, and 75); number of subtests, (2, 3, 4, 5, 6, and 7), hence the number of…

This study compares the contribution to measurement accuracy of the verbal score of each of four verbal item types included in the Graduate Record Examinations (GRE) General Test. Comparisons are based on item response theory, a methodology that allows the researcher to look at the accuracy of individual points on the score scale. This methodology…

This study explores the use of the modified caution index (MCI) for identifying judges whose patterns of recommendations suggest that their judgments might be based on incomplete information, flawed reasoning, or inattention to their standard-setting tasks. It also examines the effect on test standards and passing rates when the test standards of…