The number everyone asks about is the wrong one

The first question after almost every event is the same. How many came? Someone wants the figure for the report, the sponsor wants it for their board, and it gets quoted around like it settles everything. Twelve hundred registered, nine hundred showed up, brilliant, well done all round.

I've stopped trusting that number on its own. I've been to events with nine hundred people where most of the room was checking emails by the second session, and I've been to a quiet afternoon with eighty guests where every single person left having talked to someone they'd been wanting to meet for a year. One of those two events did its job. It wasn't the big one.

Headcount tells you how good your invitation was. It says almost nothing about whether the day was any good once people arrived. And the trouble is that a big number makes everyone relax, when a big number is exactly when you should be paying closer attention.

What you're actually looking for

So what do you watch instead? Honestly, the soft stuff. How full is the room after lunch compared to before it. Whether the Q&A has people queuing at the microphone or a long, polite silence. How many guests are still around for the last twenty minutes instead of slipping out to beat the traffic. Whether the conversations in the hallway are about the content or about where the nearest taxi stand is.

Some of this you can count. We can show an organiser, fairly precisely, which sessions held their crowd and which ones emptied out, who came back after the break and who didn't, which booths people actually stopped at rather than walked past. None of it requires you to chase anyone with a clipboard. It's just there afterwards, and it tells a far more honest story than the door figure.

A client running an annual conference for a bank told me she'd spent years optimising for attendance, pushing the registration number up each year as the headline win. The year she started looking at how long people stayed in each session, she cut the programme by a third and the satisfaction scores went up. Fewer things, better attended, properly remembered.

A packed room is a nice photo. It's a starting point, not a result. The event you want is the one people are still talking about a fortnight later, and you don't get there by counting heads at the door. You get there by being genuinely interested in what those heads did once they were through it.