What Do School‐Level Scores From Large‐Scale Assessments Really Measure?

Although assessments of mathematics, reading, and writing are assumed to measure distinct academic skills, this may be difficult owing to the pervasive influence of general ability on performance. Factor analyses of school-level data from 14 large-scale assessment programs revealed that 80% of the variance in mathematics, reading, and writing scores was due to a common, underlying factor. Multiple regression analyses confirmed that scores contribute little information that is unique to a particular subject (6% or less). Although different assessments may create the illusion of providing unique information, they may be tapping into generic cognitive abilities that cut across content areas. These results raise suspicions about the value and validity of interpretations based on school-level subject area scores.