How much behaviour change should we expect from health promotion campaigns targeting cognitions? An approach to pre-intervention assessment.

For those planning interventions based on social cognition models, it is usually not clear what impact on behaviour will follow from attempts to change the cognitions specified in these models. We describe a statistical simulation technique to assess the likely impact of health promotion targeting Theory of Reasoned Action (TRA)-based predictors of condom use. We apply regression-based simulation techniques to data from the SHARE project (n = 756 Scottish adolescents) to assess the potential impact of changes in cognitions on condom use. Results support the predictive utility of TRA-based models of psychological antecedents of condom use but also provide a cautionary warning about the magnitude of behaviour change likely to be achieved by interventions based on such models.