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Using a Logic Model to structure impact assessment


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Using a Logic Model to structure impact assessment

Julian Lomas

Much has been said and written in recent years about Logic Models and Theory of Change, not all of which has shed light on what a good Logic Model or Theory of Change is or why it is good to have one. It seems to me that it has become one of those topics that "experts" like to shroud in technical language and make as complicated as possible so that, of course, you will need to buy their services to help you construct and use your own!

At Almond Tree Strategic Consulting, most of our clients are small and medium-sized (and sometimes micro) charities and social enterprises, with limited funding and capacity. We see it as frankly unethical to try and sell our services to you when you could do it for yourselves.  We aim to build capacity and demystify not build in dependency and complexity.  And yet we frequently use a Logic Model or a Theory of Change as a framework for designing new services or projects and, in particular, for developing cost-effective impact assessment frameworks.

We use these approaches because, used well, they can provide a wonderfully simple way to break into what can often seem to be complicated territory, such as impact assessment.

What is a Logic Model?

At its core, a Logic Model or a Theory of Change is a description or illustration of why change is needed and how a service or project will achieve that change. Done well, they tell (logical) stories.  

The terms Logic Model and Theory of Change are often used interchangeably, but they are subtly different. Logic Models describe the progression from needs, to inputs and activities, to outputs, outcomes and ultimately to impacts/aims; they are essentially a description of the implementation theory behind a project or service - how the intervention will lead to the outcomes. They often lack an underlying "theory of change", that starts with the desired impact and assesses, based on evidence, what outcomes and interventions are most likely to achieve this.

Nevertheless, both  map out, or fill in, the “missing middle” between what a project or service does and how those activities lead to achievement of the desired impacts. This is illustrated in the simple logic model framework shown below.  

For our purpose here, the distinction is largely academic.  What you need to be able to do to demonstrate the impact of your project or service is tell the story (with evidence!) of what needs you are addressing, with what and how, how much you have done, what outcomes were achieved and therefore what impacts have been (or are likely to be) achieved. A simple framework like the one shown below will be more than ample for this purpose in most small and medium-sized organisations.

Simple Logic model framework.png

Telling a strong impact story

My experience is that most small charities and social enterprises can tell a pretty strong story of what they aim to achieve and what needs they are addressing (albeit the latter is often not well evidenced). When asked to evidence outcomes, most will give outputs and sometimes quality measures but not the "and so what"; evidence that the intervention or activity makes a positive difference to beneficiaries. Almost none will have any evidence of impact beyond the immediate beneficiaries of their project or service.  

Some will have qualitative evidence of outcomes or even impacts (e.g. case studies or testimonials). I do not want in any way to denigrate the value of those; they are essential to provide the audience (funders, supporters, staff, volunteers or stakeholders) with an emotional connection with what you have achieved.  

But how will the audience know this qualitative evidence is representative?

Some will take your word for it.  An increasing number won't; particularly funders who want evidence to support their decisions in an ever more competitive funding environment.

However, I do not advocate that small and medium-sized organisations should spend precious resources on expensive research projects or complicated data gathering activities unless they either have dedicated funding to do so or they are sure the benefits will outweigh the cost.  

Many could take a few relatively simple steps to gather evidence either directly from beneficiaries, through third party data or (especially for impacts) by using research evidence as a proxy. Simple surveys, gathered at the end of an intervention (and sometimes also at the beginning), need not be resource intensive to administer. Getting anonymised or aggregated statistical data from partners isn't usually difficult (if it is, getting a testimonial from them to the effect that your intervention works for most beneficiaries can be a good compromise). Spending a little time rooting out the research literature that shows how the outcomes you achieve generally cause the impacts you seek can dramatical strengthen your story.

This is where the Logic Model or Theory of Change comes in. It can, as shown in the simple framework above, give you a structure for telling the story and, show you where your evidential gaps are. It need not be complicated but it can be a very powerful way of showing the world that what you do is needed and works.

If you would like to know more about this approach to impact assessment please contact us at to arrange free initial telephone conversation about your needs.