Evidence-based management has been proposed as a method to impose rationality on decision-making, and thereby link research more closely with practice. Yet, knowledge, not evidence per se, is the means by which organizations map the uncertainty of their environments and develop strategies accordingly. This essay develops a theoretical argument to support the construct of knowledge variety, and argues that knowledge variety is a preferable operationalization of evidence-based management for organizations facing the epistemic uncertainty of complex environments. The first section sets a foundation drawing upon diversity in socio-behavioral regulation, requisite variety, the social structure of knowledge, epistemic knowledge categories, rhetorical persuasion, sensemaking, and organizational attention. The second section describes a mixed-methods project to examine evidence-based management in terms of knowledge variety across 42 hospitals associated with a common knowledge intermediary. An original proposition intending to establish a relationship between the maintenance of variety and an organization's ability to customize diffusing best practices was unable to confirm or disconfirm a relationship. Nevertheless, a series of qualitative and quantitative findings on evidence-based management and best practices are presented, including a relationship between knowledge variety and the number of years since last academic degree, suggesting the importance of revisiting the Aristotelian notion of practical wisdom (or, phronesis). Reflections, limitations, and suggestions for future research are described throughout.