Stability of the Peabody Form a Scores among First-Year Kindergarten Five-Year-Olds

Abstract

Dunn (1965) recognized that IQs on the Peabody Picture Vocabulary Test in time might fluctuate with experience of the individual. This study sought to determine the stability of Form A of the Peabody for all children enrolled in the public kindergarten in the Andalusia City School system during the 1973-74 academic year. Data were collected from 7 white females. 8 white males, 20 Negro females and 20 Negro males. The mean age of the 55 children was 64 mo., SD of 1.3 mo. on the initial test. The PPVT-Form A was administered individually to all subjects by a white female examiner during the second week of September, 1973, and again during the second week of May, 1974, approximately 8 mo. later. The data for the study were preand posttest Peabody Form A scores. Mean IQs, Pearson coefficients, and t tests for correlated measures were computed for the total sample and stratified samples by race and by sex. In addition, a standard error of estimate was calculated for the total sample. Table 1 shows that, for this sample, the second administration of the Peabody Form A gave consistently and significantly higher scores than the first. The mean IQ for the first administration was 74.82 while the mean 1Q for the second administration was 88.27. The correlation between the two administrations was ,638 ( p = ,001). The data show that when predicting Peabody Form A performance of 5-yr.-olds from initial Form A scores after approximately 8 mo. of kindergarten experience, the examiner should be willing to accept an error of approximately f l 5 I Q points with the expectation that he will be correct within this range about two thirds of the time.