A clearer but narrower Green Book
HM Treasury’s updated Green Book, published in February 2026, marks a decisive shift in how government approaches appraisal and VfM, and clarifies the link between analysis at design stage and its continuation throughout implementation.
The new edition is strikingly lean. Evaluation has been removed from the subtitle and much of the text, and detailed process guidance now sits separately in the Business Case documents. The Green Book’s role is now unambiguously focused on appraisal: identifying how objectives can be delivered, and the expected social value of different options, before funding decisions are made.
For programme designers, commissioners and delivery partners, this creates both clarity and new responsibilities.
A reframed view of VfM
The 2026 update responds to concerns raised in the 2025 Green Book Review. These included an overreliance on benefit-cost ratios (BCRs), limited attention to non-monetisable and place-based impacts, and inconsistent treatment of transformational change. BCRs remain important, but the Green Book now presents them as one input into a wider judgement that also includes distributional effects and non-monetisable benefits.
The Green Book continues to use expected social value, the ROAMEF cycle (rationale, objectives, appraisal, monitoring, evaluation, and feedback), and the Five Case Model. Because the new structure focuses on appraisal rather than how monitoring and learning work in practice, programme teams often need to carry VfM thinking forward through proportionate VfM frameworks within their monitoring, evaluation and learning (MEL) systems. This is especially important where programmes generate a mix of tangible and intangible benefits.
This reinforces a useful distinction for VfM:
- Before implementation: VfM is about expectations, and explicitly the overall balance of costs, benefits and risks, underpinned by a clear theory of change and transparent assumptions.
- During implementation: VfM becomes more granular, with the 5Es (economy, efficiency, effectiveness, equity and cost‑effectiveness) providing a practical way to understand performance, equity and value over time.
This distinction matters across government. For instance, the Department for Culture, Media and Sport, and the Department for Science, Innovation and Technology work on outcomes that are harder to monetise and often behavioural or relational in nature. The Green Book’s broader framing creates space for richer, more context-sensitive approaches to VfM. Interest is also growing in Value for Investment (VfI), developed by Julian King, which combines economic and evaluation thinking and aligns closely with this broader framing of social value.
The critical gap: connecting appraisal to evaluation
One of the most important features of the 2026 Green Book is what it leaves unsaid.
Although ROAMEF remains the organising framework, the Green Book does not explicitly link:
- the economic appraisal completed before implementation
- the monitoring systems that generate real‑world evidence
- the evaluation processes that test whether expected benefits are being achieved.
There is:
- no guidance on revisiting or refining the cost-benefit analysis during implementation
- no expectation that BCRs or benefit assumptions will be updated
- no mechanism to link MEL evidence back to the economic case.
Without these links, there is a risk that:
- monitoring is under‑specified
- political economy and delivery feasibility are not examined early enough
- programmes continue on the basis of assumptions that are no longer accurate
- VfM judgements drift away from what is happening in practice.
Monitoring is also relatively underplayed in both the Green Book and the Magenta Book. Yet monitoring is the main way programmes generate real‑time evidence and improve VfM as delivery unfolds. Treating it lightly can mean collecting data that is too generic, too late, or not aligned to the assumptions that matter most.
This is where MEL and VfM practice need to bridge the gap and strengthen the critical “feedback” or learning element of ROAMEF.
Bridging the gap: embedding VfM from the outset
Across government, demand is growing for approaches that go beyond traditional economic appraisal, particularly in departments working on culture, behaviour change, cohesion, innovation and systems change. The Department for Culture, Media and Sport evaluation strategy, for example, calls for better alignment between appraisal and evaluation, and for methods that can handle intangible outcomes.
Here, the 5E VfM criteria can support practical application of the Green Book. Developing an initial VfM monitoring and assessment framework as part of the appraisal, can help teams to:
- define ‘good value’ for the intervention, and criteria for assessing progress
- identify the assumptions that most shape VfM and need monitoring
- create a route for revisiting the appraisal during delivery
- enable in‑period VfM assessments that build on, rather than reinvent, the original analysis.
This is the approach we are using in new Foreign, Commonwealth and Development Office Kenya programmes, where early VfM framing is helping teams generate the right evidence and adapt delivery from the outset. It also builds on learning from our VfM support to the UK Government Integrated Security Fund, including how to navigate VfM in complex programmes and how to use VfM assessment to enhance the value of investments.
These lessons translate well to UK programmes with complex or hard to monetise outcomes, where broader value-focused approaches are increasingly important.
What programme teams can do
For UK Government departments
- Treat the appraisal in the business case as a living document that is revisited as evidence emerges.
- Build monitoring plans that target the assumptions that matter most for VfM.
- Use the 5E VfM criteria to complement the Green Book’s social value framing, especially for intangible outcomes.
- Ensure the theory of change and political economy analysis are in place at the appraisal stage.
For delivery partners, and global development organisations more broadly
- Build MEL systems that can test and update appraisal assumptions.
- Integrate VfM thinking across ROAMEF, not only at appraisal or funding approval.
- Bring theory of change, political economy analysis and VfM frameworks into appraisal alongside the Green Book principles.
Looking ahead
The 2026 Green Book clarifies the role of appraisal, but leaves a crucial gap: how real-world evidence should be used to refine the economic case during implementation. Revisiting appraisal is not only a technical exercise but a route to better decisions, stronger delivery and ultimately greater impact.
When programmes test their assumptions, adapt based on evidence, and refine their VfM case, they deliver more meaningful and sustainable change. For programmes seeking UK public funding, this means designing MEL systems that can test benefit assumptions, revisit BCRs and strengthen VfM over time.
Stephen Adam is an independent economist and evaluator who partners with Itad supporting UK and global social impact programmes, with a focus on VfM and evidence use.
