Relationships between performance on two preschool administrations of the Metropolitan Readiness Tests (MRT) and Stanford Achievement Test (SAT) scores at age nine were examined for a sample of 732 children. Significant correlations, ranging from .50 to .71, were obtained between readiness scores and SAT scores on reading, spelling and arithmetic. However, when subjects were classified into high and low groups on readiness and on achievement variables it was found that far greater reliance could be placed on use of high readiness scores as predictors of good academic performance than on use of low readiness scores as predictors of poor performance. (Author)