HM Treasury Green Book – what is it?

The HMT Green Book provides instructions on evaluating policies, programs, and projects. It covers the use of monitoring and evaluation in all stages of implementation.
HM Treasury Green Book – what is it?


HM Treasury released an updated version of the Green Book (2022)[1] on the 31 March 2022. The Green Book from HM Treasury (HMT) is a widely recognized guide for best practices in public sector decision-making and policy development in the UK.

The HMT Green Book provides instructions on evaluating policies, programs, and projects. It covers the use of monitoring and evaluation in all stages of implementation.

The guidance applies to public servants involved in using public resources, not just analysts. The Green Book references the Treasury’s Five Case model which is used to create proposals that deliver the most social value. The Green Book expects that all government organizations should work together to deliver joined-up public services.

The Green Book aims to provide objective advice to decision-makers in central government, appointed board members in arms-length public organizations, and elected council members in local authorities. All key aspects of public policy creation, from strategy to finance and implementation, must work together to achieve the best public value.

The Green Book approach to business case development is based on the principle of optimizing public value, and it is designed to ensure that proposals are considered in a holistic and systematic manner. HMT Green Book recommends using the Five Case Model which it developed specifically to help develop business cases. By following these stages, organizations can develop well-supported cases for investment that deliver the best outcomes for the public.

Throughout the Green Book there are links to external guidance which provide further detail on subjects that are relevant across government. For those involved in developing business cases for project and programme initiatives, there are two important guides referenced within the Green Book. These are the Guide To Developing the Project Business Case[2], and the Guide To Developing the Programme Business Case[3].

To learn more about developing a business case using the Five Case Model, a Better Business Cases course will teach you the details of how to apply the Five Case Model.

Options appraisal

Since the Green Book primarily is a guide to providing value for money decisions in the UK public sector when civil servants are developing a spending proposal, there must be a thorough options appraisal. This means evaluating the costs, benefits, and risks of alternative methods for meeting government objectives.

It uses objective evidence to inform decision making, taking into account all costs and benefits that impact the welfare and wellbeing of the population. The appraisal of social value considers non-economic factors such as environmental, cultural, and health effects, and applies to all people served by the government, not just taxpayers.


The Green Book also advises that the intervention must have a clear purpose, known as the rationale, which is set by decision-makers such as ministers in central government. Officials should then design alternative options to meet these stated objectives through objective analysis and a consideration of real options.

Longlist and shortlist

To determine the best course of action, proposals should be approached from the viewpoint of the necessary service rather than preconceived solutions or asset creation. This prevents narrow thinking and missed opportunities.

Longlist analysis

The longlist analysis and shortlist selection should take place through a workshop involving key experts and stakeholders, incorporating research findings, expert advice, and stakeholder knowledge. With proper preparation and involvement, a wide range of service scopes, delivery methods, designs, funding options, and potential unintended effects can be efficiently appraised. The reasoning behind each option’s inclusion or exclusion must be recorded and referenced as part of the longlist appraisal process.

Shortlist appraisal

In shortlist appraisal, the estimated costs and benefits of a proposed intervention are carefully evaluated, including the cost of associated risks and risk management. This stage takes into consideration the trade-off between costs and benefits from the perspective of UK society, not just the public sector or originating institution.

For example, a proposal to improve acute care services by extending an NHS building would consider the impact on the local health economy, not just the organization making the proposal. The appraisal should consider the flow of services provided to the public by central and local government, and aim to deliver joined-up, optimal public services. This understanding should guide the choice of costs and benefits used in appraisal.

Selecting the optimal option for public value for money

When developing a proposal, the “business need” must be identified. The Green Book provides methods for evaluating costs vs benefits of shortlisted options to rank them. A comparison with the current situation should consider the additional cost of non-monetary benefits and significant unquantifiable risks. The justification of proposals is based on the wider policy or program they are part of, optimizing cost efficiency when social costs and benefits are not calculable.

For example, a railway signalling system must deliver according to the program’s specifications and its benefits should not be apportioned to just the signalling component.

The final decision on the preferred option should be made considering the public value for money. This means weighing the costs and benefits, including the unquantifiable ones, to ensure that the chosen option delivers the most value to society. The Green Book provides guidance on how to determine the public value for money and make an informed decision.

It is important to remember that the final decision should not only consider the immediate benefits and costs, but also consider the long-term impact of the chosen option. The decision-makers should consider the sustainability and scalability of the option and ensure that it is in line with the wider policy or program objectives.

Selecting the preferred option requires careful consideration of the costs and benefits, as well as the public value for money. The Green Book provides guidance on how to make an informed decision and ensure that the chosen option delivers the most value to society in the long run.

Monitoring and evaluation

Monitoring and evaluation are crucial components of any proposal. Monitoring involves collecting data during and after implementation to track progress and inform evaluation. The data collected must be compared to the business-as-usual (BAU) to ensure that the set objectives are realistic and performance can be accurately monitored and evaluated.

Evaluation, on the other hand, is the systematic assessment of a proposal’s design, implementation, and outcomes. It tests if the proposal is working as expected, if the costs and benefits were anticipated, and if there were any significant unintended consequences. Evaluation also assesses the implementation process and any changes made.

All proposals must contain provisions for monitoring and evaluation, both during and after implementation. This not only helps in ensuring the success of the proposal but also provides valuable lessons that can be used to improve the design and delivery of future proposals. In short, monitoring and evaluation play a crucial role in the continuous improvement of proposals.

The Five Case Model: A Universal Framework

The Five Case Model is a comprehensive approach for making decisions on the use of public resources. It involves considering five dimensions, known as the “five cases,” that offer different perspectives on a proposal.

The model requires cross-disciplinary collaboration between policy, analysis, commercial, financial, and delivery professionals. The dimensions must be developed together to ensure they are interconnected. The Five Case Model is a universal framework that accommodates any investment or spending proposal, considering its unique features expressed as objectives or constraints.

The Green Book recommends using the Five Case Model when developing the business case for a spending proposal. The Five Cases (or dimensions) cover all aspects of an investment proposal’s viability and success.

  • Strategic Dimension – outlines the need for change and expected outcomes.
  • Economic Dimension – assesses social value versus Business as Usual.
  • Commercial Dimension – examines the feasibility of a commercial deal.
  • Financial Dimension – analyses the proposal’s impact on public finances.
  • Management Dimension – evaluates the realism and robustness of delivery plans.

The dimensions must be considered together to ensure a well-rounded evaluation of a proposal’s viability and success.


The Green Book is a key guide for public sector decision-makers as it provides a comprehensive framework for appraisal and evaluation of public sector proposals. It outlines the Five Case model, which ensures that proposals are considered in terms of their strategic, economic, commercial, financial, and management dimensions.

The Green Book also includes guidance on monitoring and evaluation to ensure that the implementation and impact of proposals are monitored and evaluated effectively. The Green Book helps to ensure that public resources are used in a transparent and accountable manner and that proposals are based on sound economic principles and the best available evidence.

By following the HMT Green Book’s guidelines, public sector decision-makers can make informed decisions that deliver value for money and contribute to achieving the government’s wider policies and objectives.

If you want to learn more about how to develop a robust business case using the Five Case Model, consider taking a Better Business Cases training course which will teach you the details of how to apply the Five Case Model to develop a business case.


[1] HM Treasury. (2022). The Green Book – Central Government Guidance on Appraisal and Evaluation. Retrieved from

[2] HM Treasury. (2018). Guide To Developing the Project Business Case. Retrieved from

[3] HM Treasury. (2018). Guide To Developing the Programme Business Case. Retrieved from

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