A validation of the Visual Perceptual Aspects Test using a bifactor exploratory structural equation modelling approach

Abstract

Visual perception is a psychological construct that describes the awareness of visual sensations and arise from the interactions of the individual or observer in the external environment together with the physiology of the observer’s visual system. A variety of theories of the development of visual perception have led to the development of different psychometric measures aimed at quantifying the cognitive construct. The Visual Perceptual Aspects Test was developed by Clutten (2009) to measure nine different constructs of visual perception. The original VPAT was validated using content and construct validity based on a Western Cape sample. However, to the researcher’s knowledge, a factor analysis had not yet been conducted on the VPAT to determine the factor validity of the test. Furthermore, no measures of validity or reliability had been conducted on the VPAT using a sample outside of the Western Cape. The aim of this research is to validate the hypothesised nine factor structure of the Visual Perceptual Aspects Test, using a confirmatory factor analysis, exploratory structural equation model, a bifactor confirmatory factor analysis and a bifactor exploratory structural equation model. The results of the analysis showed marginal model fit of the VPAT with the sample data, with sufficient levels of reliability for certain sub-tests. However, the VPAT did not meet significant levels of validity or reliability of the proposed model structure of the VPAT for the sample group of learners based in the Eastern Cape.