Insights overview


Everybody loves a (good) business case.

Trying to get permission to start that new project – you need to complete a business case.

Justify why you need that laptop… I’ll just need you to send me a business case

Want to go part-time or job share …. You get the picture.

But how can one size, or in this case document, – fit all? The answer, for the public sector at least, can be found within the 132 pages of a publication known as The Green Book.

This publication by HM Treasury, snappily subtitled “Central Government Guidance on Appraisal and Evaluation”, is somewhat of a handbook on how to make and justify decisions that involve spending from the public purse.

It introduces the concept of the “5 case model” – designed to ensure that the proposal or request has been considered from all angles and that an evidence based conclusion can be drawn. It helps to view the 5 case model as a series of “Big Questions”, with the answers being made up of answers to the more “Detailed Questions” in each of the sections – resulting in the case being proven (or not if you are unlucky!).

We have consolidated our learning into some simple top tips that have helped us and might also assist you with drafting a business case:

Tip 1:  Break it down

Before we even start writing, we like to create a RAG rated tracker, listing out every section and sub-section that needs to be included, along with guidance notes as to the content of each. This will automatically give you a sense of scale for the amount of work already undertaken and where the gaps are. It is also useful for providing a quick visual representation of progress at any given time.

We also find it gives the first time (or even the hundredth time) business case author or contributor a good overview (or reminder) of what section of the business case a particular piece of evidence supports, and identifies any co-dependencies with other work. This enables realistic timescales to be set for each contribution and the overall business case production.  Once this is complete, you may need a strong coffee or a quick lie down in a dark room for 10 minutes to steel yourself for what you’ve taken on! Or, you could…

Tip 2: Share the load  

The other advantage of the tracker is the ability to allocate individual action owners against particular sub-sections. This will help you if you are feeling overwhelmed and ward off any danger of procrastination!  While one person is often tasked with producing or owning a business case, the best results are usually gained by asking relevant experts or specialists for their input. This can be done in many ways – being asked to write a section from scratch can be daunting so why not arrange to interview your contributor, meet them face to face and talk through the questions you require answers to, and follow this up with a draft for them to review.  The only note of caution with this is approach is that you will need to ensure that the end product still reads as a cohesive piece.

Tip 3: Don’t start with the conclusion.

The “ideal” business case is one that documents a journey of information gathering and decision making. It collects and considers evidence from a wide range of sources, undertakes analysis and evaluate, consults and then – and only then – reaches a well-supported conclusion.

But – we have all been asked, at the 11th hour, to write a business case – retrospectively – to justify a pre-determined conclusion. You won’t be the first and you won’t be the last… but what do you do if you find yourself here?


Look at the work done to date, and objectively analyse it. Does it address all the questions that need to be asked? Is there something that has been obviously missed? Is there inherent bias in the assumptions that have been made? If there is something that doesn’t quite make sense, incomplete or missing don’t be afraid to say so, just make sure you also say why and what to do next.

Tip 4: Be proportionate  

Remember that the 5 case model is a framework to be used for a wide variety of purposes, so tailor it to your specific needs.

Some of the detailed questions posed may be more relevant than others in relation to your proposals, and some may not be relevant at all – and it’s ok to say that! Expressly stating that a certain factor is not relevant shows that you have in fact considered it, rather than just missed it.

Being proportionate also refers to the overall length of the business case, and the level of detail of the content. No one would expect, or want to read, a war and peace-esque document to justify a low cost and low impact spend.

Tip 5: Who’s case is it anyway?

Whilst the 5 case model is well known, every organisation, department or team has their own processes and way of working.

So before you start, ask yourself why am I being asked to produce this and who for? Double check what’s expected.  At school I was always told – make it easy for the examiner to give you the marks. The same is true for writing a business case – make it clear what you are asking for, why you are asking for it, and what difference it will make. Guide the reader through your thought processes and evidence so that by the end they can’t help but agree with your conclusion.

Some organisations have teams or department whose raison d’etre is to assure – approve or decline – business cases. They will often have their own “house” style of drafting, templates and checklists of content they wish to see. If this exists use it!

Bonus Tip: Avoid writer’s block – by writing. The hardest part is always starting, so don’t be afraid to start. It doesn’t matter if your content changes tone or location later, it’s generally easier to amend than draft.

Read Part 2: What’s in a name? here.

We explore the different types of business cases, which to use and when.

Insights overview