While the elegant parsimony of the theory of planned behavior is appealing, it is not without limitations. Research applying the theory has indicated that substantive variance in health behavior remains unexplained [14]. In addition, the size of the effect of intention on health behavior is often modest, suggesting a “shortfall” in those who report an intention to perform the behavior and those who act on their intention [15]. Researchers have, therefore, proposed modifications to the theory to resolve these limitations, such as integrating additional constructs from other theories, in the theory to predict behavior more effectively and address the intention–behavior “gap” [16].