Psychometric intelligence and achievement: A cross-lagged panel analysis

There has been considerable debate regarding the causal precedence of intelligence and academic achievement. Some researchers view intelligence and achievement as identical constructs. Others believe that the relationship between intelligence and achievement is reciprocal. Still others assert that intelligence is causally related to achievement. The present study addressed this debate with a cross-lagged panel analysis of WISC-III and achievement test scores of 289 students assessed for special education eligibility with a test–retest interval of 2.8 years. The optimal IQ–achievement model reflected the causal precedence of IQ on achievement. That is, the paths from IQ scores at time 1 to IQ and achievement scores at time 2 were significant whereas the paths from achievement scores at time 1 to IQ scores at time 2 were not significant. Within the limits imposed by the design and sample, it appears that psychometric IQ is a causal influence on future achievement measures whereas achievement measures do not substantially influence future IQ scores.