We know this much is (meta-analytically) true: A meta-review of meta-analytic findings evaluating self-determination theory.

Abstract
Self-determination theory (SDT) is a theoretical framework for addressing human motivation and wellness that has been actively and increasingly researched over 4 decades. As a cumulative knowledge base, many of SDT's fundamental tenets have been repeatedly examined. We identified 60 meta-analyses that tested many of the propositions of SDT's six mini-theories, other theory-based hypotheses, and SDT's utility in applied domains. In this review, we examine what these meta-analyses establish, highlighting the support they lend to the validity of SDT's motivational taxonomy and its hypotheses regarding the respective effects of basic psychological need satisfaction and frustration on well-being and ill-being. Meta-analytic evidence also strongly supports the relevance of SDT for organizations, health care, parenting, and education among other domains, with identifiable gaps in the meta-analytic literature. We conclude by discussing the importance of broad theory and the use of meta-analytic knowledge as scaffolding for further theory and research, albeit with its own methodological limitations.