Develop theory of change / programme theory

Theory of Change, ToC, Logic model, Program logic, Programme logic, Causal model, Results chain, Intervention logic

A programme theory or theory of change (TOC) explains how an intervention (a project, a programme, a policy, a strategy) is understood to contribute to a chain of results that produce the intended or actual impacts. 

It can include positive impacts (which are beneficial) and negative impacts (which are detrimental). It can also show the other factors which contribute to producing impacts, such as context and other projects and programmes.

Different types of diagrams can be used to represent a theory of change. These are often referred to as logic models, as they show the overall logic of how the intervention is understood to work.

Why is a theory of change used?

A theory of change can be used to provide a conceptual framework for monitoring, for evaluation or for an integrated monitoring and evaluation framework.

A theory of change can be a very useful way of bringing together existing evidence about a programme, and clarifying where there is agreement and disagreement about how the programme is understood to work, and where there are gaps in the evidence.

It can be used for a single evaluation, for planning cluster evaluations of different projects funded under a single program, or to bring together evidence from multiple evaluations and research.

When are theories of change developed?

A theory of change is often developed during the planning stage of a new intervention. It can also be developed during implementation and even after a programme has finished. ​ When an evaluation is being planned, it is useful to review the programme theory and revise or elaborate it if necessary.

How are theories of change developed?

A theory of change can be developed by programme staff, by an external evaluator, by programme designers, or collaboratively with the community.

How are theories of change represented?

The diagrams used to represent a theory of change (usually referred to as logic models) can be drawn in different ways.

Sometimes they are shown as a series of boxes (inputs->processes->outputs->outcomes->impacts), sometimes they are shown in a table, sometimes they are shown as a series of results, with activities occurring alongside them rather than just at the start. These different types are shown as different methods on this page (below).


Processes for developing a theory of change

Ways of representing a theory of change in a logic model:


A number of approaches include recommendations about how to develop a logic model as part of undertaking an evaluation:


Manager's guide to evaluation

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