The foundation of a logic model or any theory-based planning model is the identification of the behavioral antecedents and the relationship of these variables to the target behavior. Applying theoretical concepts to specific behaviors and populations is often challenging for practitioners and program planning students. The challenge comes from the abstract definition of theoretical constructs, the duplication of similar constructs in multiple theories, and the need to combine multiple theories. To simplify the planning process when utilizing logic models and health behavior theory, we recommend the use of the PER Worksheet. The PER Worksheet is a planning tool that provides layman-term prompts for identifying health behavior antecedents. It encompasses five common health behavior theories-health belief model, theory of planned behavior, social cognitive theory, an ecological perspective, and transtheoretical model. The PER Worksheet is organized into three columns: Predisposing, Enabling, and Reinforcing factors, terms of the PRECEDE/PROCEED model.