Construct validity and invariance of four factors associated with colorectal cancer screening across gender, race, and prior screening.

Understanding individuals' perceptions of colorectal cancer screening (CRCS) is important for developing effective interventions to increase adherence to screening guidelines. Theory-based cognitive and psychosocial constructs have been associated with CRCS in the literature, but few studies have evaluated the psychometric properties of such measures. We hypothesized a correlated four-factor model, including CRCS perceived pros, cons, social influence, and self-efficacy. We also examined measurement invariance across subgroups based on gender, race (white; African American), and prior CRCS experience (never; overdue for repeat screening). We used baseline (n = 1,250) and 2-week (n = 1,036) follow-up survey data from participants in a behavioral intervention trial designed to increase CRCS. Only minor modifications were made to the hypothesized model to improve fit, and the final model was confirmed with a random half of the sample, as well as with follow-up data. Results support the hypothesized unidimensional construct measures and suggest that the items may be appropriate for all subgroups examined. Greater variance in responses to items assessing the perceived cons of CRCS was found among African Americans compared with whites, suggesting that race may moderate the association between perceived cons and CRCS in this sample. Pros, cons, social influence, and self-efficacy are associated with CRCS; therefore, using scales with known psychometric properties strengthens researchers' ability to draw conclusions about group differences and changes over time and to compare their results with other studies. Replication studies in other populations are needed to provide further evidence of construct validity for the scales reported here.