Part 2 of this series, unpacks the Intervention Logic, outlining how it differs from a Theory of Change and the role it plays in mapping programmes, evaluating outcomes, and supporting clear communication with stakeholders.

This post is part two of a two-part series, with part one focusing on the Intervention Logics’ counterpart, the Theory of Change.
The Intervention Logic is a close cousin of the Theory of Change. These two models belong to a family of diagrams that includes Logic Models, Programme Logics, Programme Theories, Benefits Maps, Outcomes Frameworks, and more. This assemblage of terms can create confusion, especially as there is not always a clearly delineated differentiation between them and, in some contexts, they are used interchangeably. However, although the terms Theory of Change (ToC) and Intervention Logic (IL) lack a universal, unifying definition and format, they do have some generally agreed-upon key points of difference which can support a foundational understanding of each. These general differences are highlighted below, along with their definitions within an ImpactLab context.
A Theory of Change and Intervention Logic share a common core. They both demonstrate the chain, or flow, of direct programme inputs to the outcomes that the programme intends to achieve; they both use this flow to illustrate the causal, if-then relationships that lead to the stated outcomes; and they both support service providers to evaluate and analyse the effectiveness of their programmes. Despite this considerable overlap, the ToC and the Intervention Logic do serve distinct purposes and meet differing strategic needs.
Neither method is better than the other; each offers benefits and serves distinct communicative purposes – the flexibility of a ToC may be better for strategic visualisation and capturing higher-order, rippling impact, whereas the structured Intervention Logic may serve to better communicate the immediate and direct outcomes of a programme to funders and other key stakeholders.
At ImpactLab, ToC’s and Intervention Logic’s are broadly understood through the delineations identified above. However, there is another crucial difference in our internal framing and interpretation; a difference in ownership.ToC’s are developed and owned by the service provider. It is an articulation of their own ambitions, approaches and strategies, laying out the change journey in their own words and drawing attention to those points that they see as affecting impact.
In contrast, an Intervention Logic presents a programme through the lens of an independent, third-party Analyst. When an Analyst works with a service provider, all that they come to know about a programme through qualitative and quantitative data analysis and academic research is synthesised within the Intervention Logic. Accordingly, the Intervention Logic serves as an external analysis of a programme which can be delivered to internal and external funders with confidence, providing:
While a ToC and Intervention Logic share many similarities, they each occupy their own niche within the broader landscape of programme mapping and evaluation tools. What is right for each service provider depends on what communicative, evaluative and strategic purposes they are meeting. But, if an Intervention Logic is right for you, consider connecting with ImpactLab for your independent, third-party evaluation.
This post is part two of a two-part series, with part one focusing on the Intervention Logics’ counterpart, the Theory of Change.
The Intervention Logic is a close cousin of the Theory of Change. These two models belong to a family of diagrams that includes Logic Models, Programme Logics, Programme Theories, Benefits Maps, Outcomes Frameworks, and more. This assemblage of terms can create confusion, especially as there is not always a clearly delineated differentiation between them and, in some contexts, they are used interchangeably. However, although the terms Theory of Change (ToC) and Intervention Logic (IL) lack a universal, unifying definition and format, they do have some generally agreed-upon key points of difference which can support a foundational understanding of each. These general differences are highlighted below, along with their definitions within an ImpactLab context.
A Theory of Change and Intervention Logic share a common core. They both demonstrate the chain, or flow, of direct programme inputs to the outcomes that the programme intends to achieve; they both use this flow to illustrate the causal, if-then relationships that lead to the stated outcomes; and they both support service providers to evaluate and analyse the effectiveness of their programmes. Despite this considerable overlap, the ToC and the Intervention Logic do serve distinct purposes and meet differing strategic needs.
Neither method is better than the other; each offers benefits and serves distinct communicative purposes – the flexibility of a ToC may be better for strategic visualisation and capturing higher-order, rippling impact, whereas the structured Intervention Logic may serve to better communicate the immediate and direct outcomes of a programme to funders and other key stakeholders.
At ImpactLab, ToC’s and Intervention Logic’s are broadly understood through the delineations identified above. However, there is another crucial difference in our internal framing and interpretation; a difference in ownership.ToC’s are developed and owned by the service provider. It is an articulation of their own ambitions, approaches and strategies, laying out the change journey in their own words and drawing attention to those points that they see as affecting impact.
In contrast, an Intervention Logic presents a programme through the lens of an independent, third-party Analyst. When an Analyst works with a service provider, all that they come to know about a programme through qualitative and quantitative data analysis and academic research is synthesised within the Intervention Logic. Accordingly, the Intervention Logic serves as an external analysis of a programme which can be delivered to internal and external funders with confidence, providing:
While a ToC and Intervention Logic share many similarities, they each occupy their own niche within the broader landscape of programme mapping and evaluation tools. What is right for each service provider depends on what communicative, evaluative and strategic purposes they are meeting. But, if an Intervention Logic is right for you, consider connecting with ImpactLab for your independent, third-party evaluation.

ImpactLab Founder Sir Bill English is joining an expert panel to discuss how better connected data can drive more effective partnerships and evidence-informed decision making across the health and social care sectors.
.jpg)
The ‘use to improve’ principle is simple. It says: the best way to improve your data is to use the data you already have. Read on to find out more!
.png)
Many organisations measure their impact but struggle to talk about data findings with confidence. Here's what actually works, with practical tips from funders, fundraising experts, and charities who've done it.
.jpg)
The standards give government agencies a clearer framework for deciding what evidence they need, how outcomes should be measured, and how that evidence can be used to improve programmes and services.
We help impact organisations know, show and grow their social impact. Let’s work together to do good, better!



