This special topic paper presents key findings on the use of theories of change and logic models in TI initiatives gleaned from the following project activities: - A research summary of TI systems-level initiatives - A program scan featuring profiles of programs from diverse sectors, locations, and funding sources - A convening of experts, including researchers, policy makers, community stakeholders, practitioners, and federal leaders, held in May 2019 - A series of key informant interviews with leaders in the field, federal leaders, and federal grantees, conducted in August 2019 - An issue brief summarizing key themes and considerations for future efforts. (author abstract)