A logic model is a best-practice planning tool. It is, in many ways, like a project blueprint. In one glance, a reader can see what you want to build. You wouldn't start building a house without a blueprint, would you? Just as you don't start building a house without a blueprint, don't start "building" your project or proposal without completing a logic model first.
You can also think of a logic model as somewhat similar to a recipe. A logic model, like a recipe, describes the "ingredients" (resources) and activities that you plan to use.
A finished logic model can serve multiple purposes: 1) as a way to communicate the essence of your project idea within and outside of your project team, more quickly and effectively than you can with paragraphs of text; 2) as a "reality check" to see if you've thoroughly planned all aspects of a project; 3) as a guide to write your proposal and implement your project; 4) as a way to keep focused on what's important; 5) as an essential part of planning and implementing a strong evaluation plan.
Some grant makers require that applicants include a logic model in their proposals. Others don't require a logic model but expect to see the same information in narrative form. Either way, having a logic model will help you communicate your idea to the potential grant maker with clarity.
See our Sharepoint site for two examples of logic model templates.