How simple should a theory of change be?

TASO's Eliza Kozman attempts to strike a balance between simplicity and evaluability in understanding how interventions might have an impact on students

Eliza Kozman is Deputy Director (Research) at the Centre for Transforming Access and Student Outcomes (TASO).

Spherical cows are an in-joke among physicists.

The idea is, if you want to understand the physical world and make predictions about it, sometimes you must simplify your assumptions.

Taking a very silly example, if we wanted to calculate the speed of a skydiving cow, we might assume the cow is perfectly round and then make calculations about the forces acting on it. Sure, we won’t get a perfect picture of how an exactly ‘cow-shaped’ object acts but the model is good enough for us to make basic predictions. ‘Spherical cows’ encapsulate this way of simplifying problems so we can understand them more easily.

I love this sort of simplicity and enjoy bringing some of the same thinking to my work on evaluation. Theories of change are one example of how we sometimes take something big and complex and condense it down to its constituent parts.

A strong theory of change should form the foundation for all evaluations, and I welcome the Office for Student’s proposal that all Access and Participation Plans (APP) should be scaffolded around a theory of change which is based on the TASO template.

Everything should be made as simple as possible

In a recent article, Julian Crockford suggested this theory of change structure was insufficient to support better evaluation. In his eyes it jumps too readily from inputs to activities, and from outputs to outcomes without considering how activities lead to the desired outcomes.

But I want to speak in defense of simplicity. To stick with physics, in the words of Einstein, “everything should be made as simple as possible”. While it is true that TASO’s core theory of change template does not provide the most complete model of an intervention and how/why it works, arguably this is also a strength. It provides a high-level snapshot of how we expect an activity to (eventually) lead to impact, and does so in a format which is suitable for an audience of people who don’t work in evaluation – senior managers, policy professionals, vice chancellorss, students to name a few.

Everything should be made as simple as possible…but not simpler

However, it is true that for some audiences, this template may feel restrictive. At the heart of good evaluation, is a desire not just to identify what is effective, but why it is effective, a different template is needed to foreground those sorts of considerations.

To quote Einstein less selectively, he stated that “everything should be made as simple as possible…but not simpler”. And I believe the question of what is “too simple” depends on who you are speaking to.

A recent review of models for presenting theories of change found there is a trade-off between the requirement for simplicity and “evaluability”. Simple narratives are needed to convey overall strategic direction to audiences who can’t be assumed to have specialist knowledge. Evaluability is the extent to which an activity or project can be evaluated to a high standard, and a more detailed theory of change is required for this to be the case.

So what is the best response to these competing demands? At TASO we think our core theory of change template does a good job on simplicity, but we are also developing an enhanced version which will better support evaluation. It will provide a format for capturing much more information about activities and the mechanisms by which we expect change to happen. We are piloting this enhanced template with our partners and anticipate launching it as a companion to our core theory of change template in the new year.

When cows are spherical and when they are not

So do we think the theory of change template in the APP consultation is insufficient to support better evaluation? No. But is there space for a better tool to sit alongside it? Absolutely – please watch this space.

The real question is how we present information like this to different audiences. We are a diverse sector and it’s vital that we tailor materials to different groups so that there is buy-in to evaluation within and across institutions.

For some audiences simplicity is the most useful approach but in other cases, we need to go much further in getting under the skin of an intervention. Sometimes simple is useful, and sometimes it is reductive. For me, spherical cows can absolutely be enough, but we also need to know when to map the full bovine form, hooves and all.

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