Universal Nonverbal Intelligence Test factor invariance across deaf and standardization samples

The Universal Nonverbal Intelligence Test (UNIT) is an individually administered, nonverbal intelligence test designed for use with non-English-speaking, limited English proficient, or deaf children. The aim of this study was to assess the factor structure invariance of the UNIT across deaf and standardization samples through the use of multisample confirmatory factor analysis. Two theoretical models were evaluated: a primary two-factor (Memory and Reasoning) model and a secondary two-factor (Symbolic and Non-symbolic) model. The general forms of both models were invariant across groups, thus supporting both theoretical models. For the primary model, partial measurement invariance was found. A follow-up analysis found that the analogic reasoning measurement intercept was not invariant, indicating that the expected subtest scores for deaf examinees were lower than those for examinees in the standardization sample. In addition, the standardization sample had a higher Memory latent factor mean than the deaf sample did. The secondary model was not invariant, with three pattern coefficients differing across groups.