Factor structure of the Schalock and Keith Quality of Life Questionnaire (QOL-Q): validation on Mexican and Spanish samples.

Background: The Quality of Life Questionnaire (QOL-Q) is used widely to evaluate the quality of life of persons with intellectual disability (ID). Its validity for use with Spanish-speaking cultures has been demonstrated for individuals with visual disabilities, but not for those with physical or intellectual disabilities. Such was the purpose of the present study.
Method: Two samples were administered the QOL-Q under standardized procedures. The first sample was composed of 209 Mexican participants with physical disabilities; the second was composed of 424 Spanish participants with ID. The hypothesis tested was: the applicability (i.e. etic properties) of the measure across countries and respondents would be demonstrated if reliability data and if factor composition were similar to the original measure. Cronbach's alpha was used to test reliability and exploratory factor analyses were used to test validity (i.e. factor structure).
Results: Data indicated that the reliability and factor structure was similar to that reported in the questionnaire's standardization manual and consistent with that reported in a number of Anglo-Saxon countries.
Conclusion: The present study offers additional support for the valid use of the QOL-Q with Spanish-speaking populations.