The literature and prior research findings support the belief that motivation-related strategies must be developed to support at-risk learners in postsecondary vocational programs. Essentially, two fundamental approaches have been used to conceptualize motivation. Mechanistic approaches ignore the thinking processes of humans and stress the presence of drives that influence motivation. Cognitive, organismic approaches focus on thinking and information processing. Theory development began with the more mechanistic view and has moved progressively toward adopting a combination of these perspectives, insisting that motivation should involve basic drives or needs as well as the influences of thought processes. The Comprehensive Motivation Model (CMM) that emerged from an analysis and synthesis of the literature depicts the interactions and impact of a wide array of factors that influence postsecondary vocational students' educational outcomes. The major components of CMM are volition processing, ecological influences, cognition influences, influences related to beliefs, and influence of the emotional state. A crucial aspect of CMM is the differentiation of its intrinsic and extrinsic motives. Each component of the motivation schema could potentially be assessed. Recommendations to researchers are to expand and refine CMM's concepts, develop risk-reducing strategies related to the model's concepts, and validate those strategies' effectiveness and efficiency. (99 references) (YLB)