An examination of predictive and content validity of the Portraits Questionnaire for use with Native American and non-Native American consumers of rehabilitation services

Abstract

The purpose of this study was to examine the predictive and content validity of the Portraits Questionnaire (PQ), a universal values survey, for use with consumers of state-federal rehabilitation services. Convenience samples of Native American and Non-Native American consumers receiving services from Arizona Rehabilitation Services Administration were selected to represent the range of value priorities found in the diverse national population of rehabilitation consumers. A test for predictive validity was established by proposing a null hypothesis that the responses to the PQ by the study groups would not predict group membership. An examination of content validity was based on the logical relationship between the responses to the PQ by the two study groups and the values attributed to the two study groups in the literature. Two null hypotheses were established to test content validity. The first null hypothesis predicted that the Native American group would not assign a higher priority to PQ value types, Benevolence, Tradition, Conformity, and Security, than the Non-Native American group would. The second null hypothesis predicted that the Non-Native American group would not assign a higher priority to value types, Self-Direction, Stimulation, Hedonism, Achievement, Power, and Universalism, than the Native American group would. Copies of the PQ were mailed to 259 Native American and 263 Non-Native American consumers. Usable responses were received from 96 members of the Native American group and 97 members of the Non-Native American group. Discriminant Analysis of the data produced a significant discriminant function (Wilks' Lambda = .856, p = .001) that predicted correct group membership for 65.8% of the cases. The null hypothesis was rejected and predictive validity of the Portraits Questionnaire for the study groups accepted. Univariate analysis of the data revealed two significant (p ≤ .05) discriminant variables, Tradition and Stimulation. The standardized canonical discriminant function coefficients indicated that both variables were predictors of Native American membership. Therefore, both null hypotheses for content validity were retained. Tradition was the only value type that predicted group membership as expected. Interpretations of the results are offered and implications presented. The need for further research is discussed.