Optimal short forms of the Spanish WAIS (EIWA)

Although the Spanish version of the WAIS (Escala de Inteligencia Wechsler para Adultos, EIWA) is widely used as a measure of intelligence in Spanish-speaking populations, little is known about the psychometric characteristics of the test beyond the information given in the test manual. Despite this, users have assumed that the test functions clinically and statistically as does the original WAIS. This assumption has been applied to the area of short test forms which are assumed to be as valid as those used with the WAIS. The present study is an attempt to determine the optimal two-, three-, four-, and five-test short forms for estimation of Full Scale IQ based on the EIWA standardization test data. In addition, the relative amount of common and specific variance in the EIWA subtests was determined, along with the degree of measurement error. The study emphasizes the limitations of using the EIWA arising from its out-of-date norms, use of a restricted Spanish-speaking population, and failure to make updates since its introduction. These cautions suggest that the EIWA (long and short forms) should not be used for determining IQs; instead its use should be limited to research and to tracking cognitive changes over time.