Reliability and predictive validity of the WISC-R with native-American Navajos

The reliability and predictive validity of the WISC-R was examined with a sample of 40 Navajo children. Internal consistency reliability estimates of WISC-R subtests as well as composites were found to be low for the Navajo subjects as compared with the reliability coefficients reported in the WISC-R manual. Correlation coefficients between the WISC-R subtests and those of the Wide Range Achievement Test (WRAT) were low. Only the Block Design subtest correlated significantly with the WRAT-Spelling. The predictive validity of the WISC-R IQ scales was similarly found to be very low. Considering the nature and size of sample, cautions in generalizing these findings to other native-American populations are recommended.