Akyazi for locus of control e.g. Armitage However, Armitage et al. compared the predictive utility of self-efficacy beliefs with perceived behavioural control beliefs in relation to the use of legal and illegal drugs and found that self-efficacy beliefs were more strongly associated with behaviour than were perceived behavioural control beliefs. Self-efficacy is central to the HAPA model described later in this chapter. In a large-scale meta-analysis of studies employing the TPB, its variables accounted for between and per cent of variance in intention and between and per cent of the variance in behaviour Sutton The TPB has been tested extensively in relation to a range of health behaviour, or behavioural intention, and we can provide only a few examples here. The TPB and preventive behaviour Hagger et al. Akyazi 2016.