Reliability of the peabody picture vocabulary test: A review of 32 selected research studies published between 1965 and 1974

This report is a review of reliability data on the PPVT obtained from 32 research studies published between 1965 and 1974. Much of the research was done on Head Start children. Overall, the median of reliability coefficients reported here (0.72) has remained remarkably close to the original median of 0.77 found in standardizing the test. Unexpectedly, elapsed time between test and retest had only a slight effect on the reliability coefficients. However, as expected, the greater range in ages and ability levels of subjects, the higher were the reliabilities. For average children in the elementary grades, and for retarded people of all ages, PPVT scores remained relatively stable over time and there was close equivalence between alternate forms. Scores were least stable for preschool children, especially from minority groups. Black preschool girls were more variable in their performance on the PPVT than boys, and preschool girls generally were more responsive than boys to play periods conducted before testing was begun. A number of variables associated with examiners and setting affected the scores on the test. As expected, raw scores tended to yield slightly higher reliabilities than MA and considerably higher reliabilities than IQ scores.