The worst case goes up on the screen. Somebody reads the total out loud. There is a short silence, and then it comes.
“That is the worst case. We are never going to be that unlucky.”
Everybody agrees. The number comes off the slide, and the meeting moves on, feeling that something sensible has just been done.
They are right, by the way. That is the part worth sitting with.
The worst case assumes every identified risk materializes. All of them. The supplier is late, and the integration fails, and two of the three people who understand the legacy system resign in the same month, and the regulator changes the rules in October. That is not a forecast. It is an inventory of everything that could go wrong, added up as though it all will.
So no. It will not be that bad.
Both ends of the same stick
Now look at the other number, the one nobody ever deletes.
The best case assumes no risk materializes at all. Not one. Every supplier delivers on the agreed date, every requirement survives first contact with the business, the integration works the first time it is tried, nobody resigns, nothing turns up in testing that was not already known, and the regulator stays quiet all year.
Read that back. It is exactly as ridiculous as the other one.
Commit the following to memory (tattoo it if you must): the Best Case is as unlikely as the Worst Case.
Think of the United States at the Olympic Games. The worst case is that it goes home without a single medal. The best case is that it wins every medal on offer.
Both are nonsense, and for the same reason. It has never come close to either. It takes a great many, and not all of them, every time, and anybody who follows the Games has a rough idea of the range before the opening ceremony.
Nobody plans the parade around every medal. In a project meeting, every medal is the only scenario anyone writes down.
And then somebody dares to ask the question that finishes the job.
“Is there anything else we can take out of this?”
At this point, one is tempted to inquire: which part of “Best Case” do you not understand? Do you intend to win more medals than exist?
The pretty number does not stay in the room
This matters more than an argument about arithmetic, because of where that number goes next.
The best case does not sit quietly in the minutes as a bookend. It goes into next year’s budget. From the budget into a business case, from the business case into somebody’s target, and by the time the first risk materializes, the figure has been repeated in so many meetings that it has stopped being an estimate and become a commitment.
So when the supplier is late in month four, the project is not merely late. It is over budget against a number that was never a forecast. The team then spends the rest of the year explaining the difference between what happened and what was never going to happen.
Nobody wanted that outcome. Everybody voted for it in March.
What the two numbers are for
The bookends were never forecasts. They are the width of the corridor. They say how far the outcome can move, which is a different and more useful thing than saying where it will land.
The number to plan against is neither of them. It is the Expected Case: each identified risk priced for what it costs if it happens, weighted by how likely it is, and added to the base estimate. That gives a figure higher than the best case and lower than the worst, and unlike either bookend, it can be defended line by line.
Then put the contingency on its own line, with the risks it belongs to named beside it. Not folded into the total, where it looks like padding and gets shaved. On its own line, where taking it out means somebody has to say out loud which risk they have decided not to fund.
Present all three and say what each is for. Best Case is what happens if nothing goes wrong, and nothing has ever gone nothing-wrong. Worst Case is the exposure if everything hits you at once. Expected Case is the number the project will actually be run against.
That last one is the only sentence in the meeting that anybody will be held to.
The United States has never won every medal at the Games.
It has never gone home without one either.
Only one of those two numbers tends to be written into a budget.