Theory of change

What is a theory of change?

A theory of change shows the parts of an intervention, the intended outcomes and impacts, and how the intervention is expected to bring about change. Creating a theory of change is the first step to planning an evaluation.

A theory of change describes the underlying assumptions about how planned activities will lead to intended outcomes. By developing a theory of change, you can understand how different aspects of your programme fit together to achieve your final goal.

A theory of change model allows you to describe:

• the need you are trying to address (your problem statement)
• the changes you want to make (your outcomes)
• how you plan to achieve these changes (your activities).

At TASO, we distinguish between a high-level Core Theory of Change and a more detailed Enhanced Theory of Change. 

Why do I need a theory of change?

A theory of change supports the following processes:

Designing effective interventions: A theory of change prompts you to identify the outcomes and impact you expect your intervention to lead to. This allows you to design interventions which can realistically achieve the desired outcomes, given the resources available. It also allows you to critically assess the intervention you have designed and be transparent about how it will lead to the long-term goal. Constructing a theory of change can reveal assumptions and flaws in the logic of an intervention, helping to test the rationale for implementing an intervention as planned. 

Aligning stakeholders: The process of constructing a theory of change in a collaborative manner helps organisations to think through what they do and why. It offers an opportunity to engage stakeholders and ensures that everyone is aligned about an intervention’s implementation, aims, and how it is expected to work. It offers an opportunity for meaningful reflection. As a living document, a theory of change can support the iterative process of intervention design and development, by using evaluation findings to inform adjustments to the intervention. 

Planning an evaluation: A theory of change model helps you to identify questions and sources of evidence for an evaluation. The evaluation will assess whether the outcomes, impacts, and causal pathways identified in the theory of change have emerged as expected. Applying evaluation findings to an intervention’s theory of change serves as a first step to inform changes in practice to make interventions more effective. 

How do I develop a theory of change?

You can use the Theory of Change Builder to create your diagram, or one of our static templates: Core Theory of Change and Enhanced Theory of Change.

Follow these steps to create your theory of change:

1. Start with your problem statement

Clearly define the problem you want to address. What is the issue, who is affected, and why is this a problem? This anchors your theory of change in a shared understanding of the need for action.

2. Involve the right people

The process of creating a theory of change is often just as valuable as the final document itself. Doing so collaboratively helps build shared understanding and buy-in. 

Who to involve depends on your goals:

• To evaluate existing work: Involve a small group of practitioners and evaluators who understand the current intervention.
• To design a new intervention: Add researchers, subject experts, and likely participants (for example, students).
• To gain buy-in: Include people you want to persuade, such as delivery staff, senior leaders, or partner organisations.

Run an initial workshop, ideally with a skilled facilitator, to guide the process. You might start with a blank template or bring a draft theory of change for participants to review and work from. Afterward, refine the draft with a smaller team.

3. Choose where to begin in the theory of change

Depending on the stage of your initiative:

• If the initiative is new, start with the outcomes and impact you hope to achieve and work backwards. This helps ensure your activities are purposefully designed to reach your goals.
• If the initiative is already running, it’s often easier to start by identifying the current activities, then map the outcomes those activities aim to achieve.

Start with the section you’re most comfortable with and build out from there. You will probably go back and forth between sections as you develop your theory of change.

4. Define clear, specific outcomes

Outcomes are the changes you expect to see as a result of your work. Be precise about what will change, for whom, and in what timeframes. Make sure your outcomes are measurable and meaningful. 

5. Map causal pathways

Now, connect the dots and outline how your activities lead to your outcomes and what mechanisms or processes make the change happen, ensuring that each activity clearly relates to an outcome. Be logical and explicit about the links in the theory of change.  This section is key to your theory of change, as it helps to clarify how change happens.

6. Identify assumptions and contextual factors

Every theory of change rests on assumptions and is influenced by its context. Consider what must be in place for your initiative to work and what external or internal factors could influence success. Capturing these makes your theory more realistic.

7. Keep it clear — simplify if needed

If your theory of change diagram gets too complicated (for example, lots of arrows, loops, or overlapping elements), consider:

• Focusing on a narrative description alongside the diagram (see Enhanced Theory of Change template)
• Breaking the theory into smaller parts for different audiences
• Prioritising the most important causal links and outcomes.

The goal is clarity, not complexity.

8. Adapt and update as you learn

A theory of change isn’t set in stone. Treat it as a living document that you review and update as your context changes and new evidence emerges, and use it to inform ongoing reflection and improvement.

9. Tailor your theory of change to your audience

Finally, consider who will use the theory of change and tailor it to their needs. This might mean making different versions of one theory of change for different audiences.

• Practitioners may need more details about the inputs and activities involved in the intervention’s delivery.
• Funders or leaders may want to see the rationale and evidence behind the intervention, and that it is likely to lead to success.
• Evaluators will look for clear outcomes and indicators of success.

Use the level of detail, language, and presentation format that best meets your audience’s needs.