Understanding Voluntary Intentions within the Theories of Self-Determination and Planned Behavior

This survey study aimed to test the usefulness of an integrated model that combines self-determination theory (SDT) and the theory of planned behavior (TPB) in explaining volunteers’ intention to continue. Participants (N = 284) completed a survey form measuring the psychological constructs derived from SDT (i.e., autonomous and controlled motivations) and the TPB (i.e., attitudes, subjective norms, perceived behavioral control [PBC], and intention). Results of path analysis showed that autonomous motivation positively predicted attitudes (β = 0.47, p < 0.01) and PBC (β = 0.39, p < 0.01). Conversely, controlled motivation was negatively associated with attitudes (β = -0.16, p < 0.01) and PBC (β = -0.18, p < 0.01). Attitudes (β = 0.39, p < 0.01) and PBC (β = 0.49, p < 0.01) were then positively related to intention. The integrated model is generally supported in the context of volunteerism, and it may better explain voluntary retention than only use SDT or the TPB.