Predicting adherence to COVID-19 behavioural guidelines: a comparison of Protection Motivation Theory and the Theory of Planned Behaviour

Abstract

Objective To compare the utility of Protection Motivation Theory (PMT) and the Theory of Planned Behaviour (TPB) for understanding diversity in adherence to COVID-19 behavioural guidelines. Methods and measures A representative sample (N = 600) completed two online questionnaires: One that included measurements of PMT and TPB components that predict behaviour, and another (after one week) consisting of adherence to COVID-19 behavioural guidelines. TPB was represented by a single model, while PMT was represented by three models: Model 1, which did not include a measure of protection motivation; Model 2, which included protection motivation – represented by behavioural intentions; and Model 3, which was similar to Model 2 and included a direct link from self-efficacy to behaviour. Results The TPB model displayed the best fit-to-complexity ratio (i.e. information criterion), and its capacity to explain adherence was similar to PMT Models 1 and 2, but lower than Model 3. Conclusion The findings highlight the need to reach a consensus regarding the definition and measurement of protection motivation. While the TPB model exhibited superior fit-to-complexity ratio, variance was better explained when self-efficacy was included, and interventions may benefit from targeting different constructs depending on the context.