Phase 1 - Define

1.1 Develop a logic model

A logic model – sometimes called a ‘theory of change’ – lays out the key project inputs, outputs and outcomes. Its purpose is to clarify the work being done and the aims and benefits of that work.

Developing a logic model is often the first step in developing a SIB, because it helps to describe and define more tightly:

  1. Who exactly the service best works for
  2. What precisely the outcomes are for these beneficiaries (in a ‘SMART’ format)
  3. What success rate, or volume of outcomes, the designed service might achieve
  4. How success can be monitored and managed

A good theory of change will set you up well for successful delivery and performance management.

As well as services and consultancies who can facilitate the process, there are a number of online tools to help walk you through the creation of a logic model:

Those who have developed logic models with a SIB specifically in mind have told us that:

  1. The theory of change process in its purest form asks organisations to go right back and revisit their mission. Be ambitious but not too lofty if you want to use this as a basis for a realistic SIB. Done right, a SIB tied firmly to a provider’s organisational mission is most likely to run smoothly
  2. The most useful part of the process from the perspective of SIB development is the attaching of precisely defined indicators to your outcomes, and the mapping of data requirements to measure them
  3. To ensure that all voices are heard and to challenge confirmation bias (especially within organisations trying hard to make a SIB work), an external facilitator can be invaluable. Ignoring frontline or beneficiary voices can endanger a SIB as surely as it can endanger an entire organisation
  4. Record assumptions: these can often be the details that need testing during SIB scenario modeling. Logic models can err towards the best case, and in SIB delivery we often deal with more complex reality.

Masterclass: The right questions

Bethia McNeill, Centre for Youth Impact

The two questions that are really important to a theory of change are:

  1. Why are you proposing to do what you do?
    • With some reference to context – what’s going on in the community’s lives, what is their reality?

    • Should draw in underpinning theory. If you are going to do a 10 week basketball programme: why basketball? Why 10 weeks? Is there a body of practice or evidence to support this?

  2. What is it that you are doing?​
    • Aims, goals, work towards one or two sets of outcomes

    • Activities – and within that, what we call the ‘mechanism of change’: the experience or even the moment that creates change.

    • Which parts are flexible? With reference to inclusion criteria, programme duration

Answering those two deceptively simple questions meaningfully should be quite challenging and should involve conversations with others. If it feels easy, press a little bit harder: keep digging into the details, always asking ‘why?’


A theory of change needn’t involve inventing a completely new service. There is an emphasis on innovation with many SIBs – understandable for a funding mechanism which often focuses on intense, unresolved social needs. But in a lot of cases, this is misguided or artificial. Innovate only when:

  • You have a good understanding of your starting point, and
  • You have a hypothesis as to what is and isn’t currently working

This may not be exciting, but it avoids the risk of reinventing the wheel or going off on a tangent to your mission.

Further resources

Next: 1.2 Define your target population