Utilisation is the number most professional services firms watch more closely than any other. It may also be the most misleading.

Not because it's wrong, but because of what we assume it means. Utilisation measures how full your people's diaries are. We tend to hear it as a measure of how well those people are being used, which is a far bigger claim than the number can actually support.

It's an easy assumption to make, because utilisation looks like rigour. It's clean, it's comparable, it sits on every dashboard, and when it dips it gives everyone something clear to do. Few numbers feel more like control, which is exactly why it gets trusted more than it deserves.

Watch what happens when a firm decides its utilisation is too low. The whole place mobilises to lift it. Book more, bill more, get people onto work. It feels like decisive management, and sometimes it is. But a firm can be told its utilisation is too low, drive it up, and destroy value in the process, because the number was never able to say whether people were busy on the right things.

Look at where that pressure lands, and you find it on people, not spreadsheets. The consultant booked onto whatever's available rather than what fits, because the empty slot is the thing being measured. The senior person doing work a junior could do, because billed beats idle this quarter. The high performer sitting at ninety per cent, who looks like a star on the report and is actually stretched thin across the wrong work, edging towards burnout while the dashboard glows green.

None of it is anyone being reckless. Everyone is responding, sensibly, to the number they're measured against. And the number is doing exactly what it was built to do. It counts how full the diary is. It was never designed to notice whether the hours inside it are the right hours. A fully booked week and a well-spent one can look identical on a report and be nothing alike underneath.

The gap between them has a cost, and it's a real one. Margin leaks quietly, as fixed-fee work absorbs more senior time than it was priced for. Good people tire and disengage, not from being under-used but from being heavily used on work that neither stretches nor suits them. And the firm makes confident decisions on a number that cannot actually see whether it is winning or losing.

I'm not suggesting anyone stop measuring utilisation. It matters. A firm that isn't deploying its people isn't generating revenue, and that becomes existential quickly enough. The point is to hold the number more lightly, and to treat it as one signal among several rather than the target the whole business is steered by. The leaders I've respected most never asked only whether their people were busy. They asked whether they were busy on the right things, and whether the firm would even know if they weren't.

That second question is the harder one, and the more valuable, because the information that answers it does exist. It lives in the daily experience of the people doing the work, who can usually tell you long before any report can whether their time is being well spent. It simply rarely reaches the dashboard in time to matter.

That's the thread that runs through everything I write, and through the book. The most useful intelligence a firm has about its own people is often the intelligence it isn't measuring. Utilisation is just the most obvious example.