Understanding contribution analysis in A Better Start’s national evaluation

In September, researchers from NatCen presented details of how the national evaluation is structured around testing different ‘contribution claims’. While we’ll have to wait until 2026 for the final results to become available, the webinar was a valuable opportunity to see how researchers approach the complex job of understanding the impact of A Better Start.

What contribution analysis is

When it comes to improving the lives of babies and young children, there is rarely a single silver bullet.

That is especially true for A Better Start (ABS), a 10-year, £215 million programme funded by The National Lottery Community Fund. ABS has worked across 5 distinct areas of England to support families and improve outcomes for babies and toddlers, through more than 120 interventions co-produced with local communities.

From supporting nutrition and language development to enhancing emotional wellbeing, ABS is ambitious in scope and deeply embedded in local systems.

But here’s the challenge: how do you evaluate the impact of a programme that is just one part of a bigger picture?

That’s where contribution analysis comes in.

Contribution analysis is a method used to assess the role an intervention plays in achieving outcomes, especially when those outcomes are influenced by many other factors. It doesn’t try to isolate ABS as the sole cause of change. Instead, it asks: what contribution did ABS make, and how do we know?

In complex ecosystems like those that ABS operates in, where local services, national policies and ‘social’ dynamics (like housing and access to green spaces) all interact, contribution analysis helps evaluators build a credible case for how and why change happened.

Why ABS needs a complexity-aware evaluation

ABS isn’t a simple programme. It spans multiple policy domains, involves a wide range of people and organisations, and operates in areas where other initiatives are also underway.

With complex systems like ABS, more traditional evaluation methods, which often assume a straight line from intervention to outcome, aren’t always fit for purpose.

Instead, ABS’s national evaluation, led by NatCen in partnership with RSM UK, Research in Practice, the National Children’s Bureau and the University of Sussex, takes a complexity-aware approach. It is designed to be flexible, responsive and grounded in the real-world contexts that families raise their children in.

How contribution analysis works in practice

The evaluation team is using contribution analysis to explore 4 key questions:

• what contribution has ABS made to children’s life chances?
• what factors have helped improve children’s nutrition, emotional wellbeing and communication skills?
• what are families’ experiences of ABS services and support?
• has ABS helped reduce public spending related to primary-aged children?

To answer these, the method follows a step-by-step process. It starts with analysing the Theory of Change (ToC). The ToC can be seen as an articulation of how ABS is expected to improve outcomes. Each of the 5 ABS partnerships has its own ToC, alongside a national version developed by the Fund. These theories help evaluators map out the assumptions, pathways and context behind the programme.

Then, using a wide range of evidence, from local evaluations to national data, the team tests what’s known as a contribution claim. For example: did ABS interventions help improve babies’ and toddlers’ diet and nutrition in a particular area? If so, how do we know it was ABS, and not something else?

A collaborative approach to evaluation

One of the strengths of this approach is its collaborative nature. The Fund, the national evaluation team, the 5 local partnerships and families themselves all bring different perspectives, expertise and insights. The evaluation team brings this data together, interpreting it, challenging assumptions and identifying the part A Better Start has played.

As the Fund puts it: “As a funder we were keen to understand the contribution that ABS made towards achieving its aim and objectives. The use of contribution analysis for the national evaluation recognised how ABS sites operated in complex contexts and how ABS was only one component in what was taking place in local sites to address early childhood development.”

Why it matters

In a world where public programmes are increasingly expected to demonstrate impact, contribution analysis offers a realistic and nuanced way to do just that. It acknowledges complexity, embraces uncertainty and focuses on building a credible narrative of change.

For ABS, that means being able to show how its work, from national programmes like HENRY to local innovations like Bradford Doulas, has made a real difference in children’s lives.

For funders, policymakers and practitioners, it means having robust evidence to guide decisions, improve services and ultimately help give every child the best possible start in life.

Find out more about the national evaluation of A Better Start and how it uses contribution analysis in the national evaluation webinars.

A Better Start – National Evaluation Annual Report Webinar

YouTube: Third Annual Update from A Better Start – National Evaluation

About A Better Start

A Better Start is a 10-year project set up by The National Lottery Community Fund, the largest community funder in the UK.

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The National Children’s Bureau is coordinating an ambitious programme of shared learning for A Better Start, sharing the partnerships’ experiences in creating innovative services so that others working in early childhood development or place-based systems change can benefit.

The National Children's Bureau - A Better Start