The cornerstone of an effective evaluation is an intimate understanding of the program under consideration. Hence, logic models can be very useful in evaluation planning since they provide the evaluator with a visual depiction of how the program is supposed to work. Logic models can help evaluators better match the evaluation to the program by helping them focus on critical components of the program. As an advance organizer, the logic model aids the evaluator to focus on the important elements of the program and to identify what evaluation questions should be asked and why, as well as what measures of performance are key. If a particular result is included in the logic model then it generally should be included in the evaluation as a factor to track and measure. The logic model can help the evaluator prioritize where to spend the limited resources allocated to the evaluation. It helps the evaluator focus more specifically on what information stakeholders really need to know about the program. If a logic model does not exist when the evaluator is hired, it will be extremely useful if the evaluator in collaboration with various stakeholders works to create one.