What's the difference between a program logic and a theory of change?
The world of evaluation can be full of confusing terminology.
Evaluators will often refer to program logic models. These are essentially diagrams that describe how a program is supposed to work. They include program inputs (e.g. what resources are available), outputs (what is produced), and desired outcomes (what is supposed to happen as a result). For example:
Similar to program logic models are theories of change. A theory of change describes how activities produce a series of results, that contribute to achieving the final intended impacts. For example:
So what's the difference between a program logic model and a theory of change? The terminology (and use) of these can be interchangeable, and can mean different things to different people. There have been a few differences identified, although these aren't always hard and fast. Simply put:
- Theories of change focus more on the outcomes of a program, rather than its inner workings
- Theories of change sometimes show the bigger picture, whereas program logic models focus more on the 'micro' of the program
- Theories of change often include issues related to the environment or context that the program itself can't control
- Theories of change often show all the different pathways that might lead to change, even those not related to the program, whereas program logic models are more focused on the program in question
- You can get a bit more creative with a theory of change; they often include feedback loops and different branching pathways, whereas program logic models tend to follow the same format.
Again, these are by no means hard and fast rules. Program logic models are increasingly incorporating things like contextual factors and assumptions. The important thing is that both of these tools provide a way of explaining how a program is supposed to work in changing an outcome. Whichever one is chosen should depend on what makes most sense for the particular program/context in question.
And you can still get creative with a program logic model:
For further reading:
https://www.betterevaluation.org/en/resources/guide/theory_of_change