Integrating self-determination theory and the theory of planned behaviour to predict intention to donate blood.

Abstract

The aim of this research was to test a model integrating self-determination theory (SDT) and the theory of planned behaviour (TPB) to predict intention to donate blood. Social science research suggests that motivational orientations outlined by SDT can be usefully integrated with constructs from the TPB to collectively predict intention and behaviour. Such analysis has not yet been undertaken in the context of blood donation. A total of 458 currently eligible donors completed measures of blood donor motivations, attitudes, subjective norms, perceived behavioural control (PBC) and intention. Path analyses modelled the direct and indirect effects (via TPB constructs) of motivational orientations on intention. SDT motivational orientations explained an additional 14% of the variance in blood donation intention, compared to a TPB-only model. Amotivation had a negative direct effect on intention; external regulation had no overall effect on intention; introjected regulation had positive direct and indirect effects on intention; and autonomous motivation predicted intention both directly as well as via attitudes, subjective norms and PBC. This research provides the first evidence that integrating SDT and the TPB is a useful approach in donor research, particularly for specifying plausible pathways through which motivational orientations impact intention to donate blood.