Validation of Wechsler Adult Intelligence Scale-Fourth Edition (Wais-Iv) in the Ghanaian Population

Abstract

This study examined the validity and reliability of WAIS-IV amongst a Ghanaian sample. It also developed local norms on the WAIS-IV to be used in Ghana and examined the factor structure of the WAIS-IV. A sample of two hundred and fifty one (251) healthy students and workers was selected from two Senior high schools and the University of Ghana, Legon in the Greater Accra Region of Ghana. Through the use of a cross sectional design, participants of this study were sampled using a purposive sampling technique. The participants of the study were administered both the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) and the Raven’s Standard Progressive Matrices (SPM). A Two-Way Analysis of Covariance (ANCOVA) using educational years as a covariate showed that there were significant age and sex-related differences in performance on the WAIS-IV and it indices. Also, results from the analysis using Pearson Product-Moment Correlation Coefficient showed that the Standard Progressive Matrices which is a non-verbal test of intelligence correlated significantly and strongly with WAIS-IV indices (PRI and PSI) that measure non-verbal intelligence than with WAIS-IV VCI which measures verbal intelligence. Moreover, through the use of Paired Samples t-test it was found that there were significant differences between the American published norms and the Ghanaian norms developed from this study on the WAIS-IV. In addition, the four-factor structure of the WAIS-IV was not confirmed. The implications of these findings were discussed in relation to clinical practice in Ghana. It was concluded that there are potential cultural biases in Western imported psychological tests and hence the need for these tests to be validated before being used in Ghana.