Long-term stability of the Wechsler intelligence scale for Children - Third edition

Long-term stability of the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; D. Wechsler, 1991) was investigated with a sample of 667 students from 33 states twice evaluated for special education consideration. With an average test-retest interval of 2.87 years, test-retest reliability coefficients for the Verbal IQ, Performance IQ, and Full Scale IQ were .87, .87, and .91, respectively (p < .0001). As expected, test-retest reliability coefficients for the subtests were generally lower than for global IQ and factor index scores. Mean differences from first testing to second testing were either not statistically significant or not clinically meaningful. Results provided the highest estimates of long-term stability for the WISC-III yet reported.