This special topic paper outlines the rationale for using and supporting logic models grounded in theories of change to help build the TI evidence base. It draws from information gleaned from our research summary, program scan, key informant interviews, and observations as technical assistance providers to: - Describe theories of change, logic models, and theory-based logic models - Highlight the importance and benefits of a clearly specified roadmap throughout implementation - Discuss common challenges to developing and implementing a theory-based logic model in TI initiatives - Share strategies for federal, state, and organizational leaders and funders to facilitate the use of theory-based logic models It also presents a sample, theory-based logic model and hypothetical scenarios illustrating its use by a fictional agency. (author abstract)