Composite scores are often formed from test scores on educational achievement test batteries to provide a single index of achievement over two or more content areas or two or more item types on that test. Composite scores are subject to measurement error, and as with scores on individual tests, the amount of error variability typically depends on…

Best practice in gifted and talented identification procedures involves making decisions on the basis of multiple measures. However, very little research has investigated the impact of different methods of combining multiple measures. This article examines the consequences of the conjunctive ("and"), disjunctive/complementary…

The literature on measurement reliability shows the consensus that group heterogeneity with regard to the trait being measured is a factor that affects the sample measurement reliability, but the degree of such effect is not entirely clear. Sample performance also has the potential to affect measurement reliability because of its effect on the…