How to Note: Developing a Project Logic Model - USAID (n.d.)

During USAID’s project design process, teams must develop a theory of Change (TOC) describing how and why a project purpose is expected to be achieved in a given context, and an accompanying logic model providing a graphic or visual depiction that summarizes this TOC. 

A complete TOC includes five components:
1. The context in which the development problem is situated;
2. If-then (causal) outcomes needed to achieve the desired change;
3. Major interventions that USAID and others will undertake to catalyze these outcomes;
4. Key assumptions that underlie the success of this theory; and
5.Key indicators to monitor how progress unfolds during implementation

The logic model is a snapshot or approximation of this TOC; it is not an exact representation, and often does not include all of these elements. What is highlighted in the logic model will depend on its intended application and the degree of detail that the team opts to include in this summary presentation.