Honesty Starts at the Top, and Delivery Can Ask for It
How delivery professionals can shape the business cases and strategies they inherit
3 minute read | For delivery professionals.
Delivery teams inherit every number a business case ever promised. You are the people who find out, on site, whether it was true. That gives you something business case writers and strategy planners rarely have: evidence. It also gives you a good reason to use it early, and to expect a hearing.
The client sets the weather
Every value chain takes its cue from the client. Reward the confident bid over the honest one and the designer learns to inflate the benefits, the contractor learns to price around the gaps, and the supplier learns to say yes now and explain later. Behaviour travels downstream faster than any instruction does.
The scale of the problem is well documented. Flyvbjerg (2008) found inaccuracy in cost forecasts for transportation infrastructure projects was on average 44.7% for rail, 33.8% for bridges and tunnels, and 20.4% for roads, and that the pattern had not improved over decades of data. Some of that is optimism bias: honest people looking only at their own project. Much of the rest is strategic misrepresentation: numbers bent because approval rewards the bid, not the outcome. Both are shaped by what the client visibly rewards.
Public money makes the client’s duty plain. Managing Public Money asks accounting officers to test spend against four standards: regularity, propriety, value for money and feasibility (HM Treasury, 2026). Feasibility asks whether the work can really be delivered, to time, with the resources available. An accounting officer cannot honestly sign that off on fiction, and delivery people are best placed to say where the fiction is. This is the basis of what PAS 4010 is seeking in a ‘line of sight’; strategy right through to outcome.
Where the cost lands
A risk softened in the business case does not disappear. It arrives on your desk as a compressed programme, unfunded scope, or a contingency spent before you were appointed. Productivity is lost where truth is lost, and it compounds at every hand-off. Delivery is left holding the rework bill and, often, the blame.
How to influence what you did not write
Complaining after the event changes nothing. Bringing evidence early, in a form planners can use, changes a lot:
Bring the reference class. What really happened on the last five projects like this? Your own lessons learned beat any non-delivery-based forecast.
Offer ranges, not single points. Say what you know, what you do not, and what would improve confidence in the number.
Ask the feasibility and do-nothing questions in the room where the case is written, not in the post-project review.
Ask for an ex-post evaluation to be committed up front, so that today’s numbers face tomorrow’s outturn.
Frame it as protecting the client, because it is. A case that survives contact with delivery evidence is one the accounting officer can defend in front of the Public Accounts Committee.
A word to clients
You set the weather, so set it deliberately. Reward whoever brings bad news early. Keep appraisal separate from promotion. Ask for ranges and read them. Carl Gomersall’s Sophiotelic doctrine puts it bluntly: governance that cannot tell the truth under pressure is choreography. If your team can only tell you what you want to hear, the chain below you will do the same, and the purpose you funded will quietly drift.
This week, find the business case your current project rests on. Pick one assumption you know from experience is too optimistic. Take it, with your evidence, to the person who wrote it, and ask: what would change your mind?
References
Flyvbjerg, B. (2008) ‘Curbing optimism bias and strategic misrepresentation in planning: reference class forecasting in practice’, European Planning Studies, 16(1), pp. 3-21.
HM Treasury (2026) Managing Public Money. London: HM Treasury. Available at: gov.uk.
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