Developing a Logic Model
Updated November 17, 2020
Disclaimer: The activities in this document are intended for example purposes only. The actual activities implemented as part of TB program evaluation should be identified by state or local TB program officials in collaboration with other stakeholders. The example provided here is not intended to be applied directly to any specific TB program.
A logic model illustrates the association between your program’s resources, activities, and intended outcomes. Logic models can:
- Vary in size and complexity
- Focus on a specific aspect of your TB program, such as a single evaluation question or objective, or encompass the entire program
- Be used to develop evaluation plans
- Be revised and updated to reflect changes in activities, new evidence, and lessons learned
Logic models are useful tools for program planning and evaluation because they:
- Guide staff in thinking about and evaluating their program
- Identify assumptions and potential challenges
- Assist in identifying intended programmatic outcomes
- Organize, connect, and identify gaps in evaluation efforts
Thinking of a logic model as a series of if . . .then statements will be helpful. The following graphic was designed to illustrate the idea of using if . . . then statements in developing a logic model for your program. The source content for the graphic and accompanying logic model component definitions are adapted from CDC’s Division for Heart Disease and Stroke Prevention’s comprehensive guidance on developing a logic model.
- Inputs are the resources (dollars, staffing, and materials) that go into a program or intervention — what we invest.
- Activities are events undertaken by the program or partners to produce desired outcomes — what we do.
- Outputs are the direct, tangible results of activities — what we get.
- Outcomes are the desired results of the program — what we achieve.
- Short-term outcomes are the immediate effects of the program or intervention activities.
- Intermediate outcomes are the intended effects that occur over the midterm of the project period.
- Long-term outcomes refer to the desired program results.
The following logic model example accompanies the evaluation plan for Completion of Treatment for Tuberculosis Disease by Using Incentives and Enablers. Other ways to structure a logic model can also be used. CDC’s Program Performance and Evaluation Office provides additional examples of simple and complex logic models and checklists for developing them.