It’s actually more complicated than you think.

For most events, music or otherwise, measuring the crowd size is an important metric. In ticketed events, it’s a relatively simple process of counting gate receipts.

But for unticketed events, it’s a bit more complex, yet it’s a frequently required exercise. From New York’s SummerStage concert series to Chicago’s recent Cubs championship parade to DC’s… you know what, I can’t think of an example for DC.

Anyways, the classic method for estimating crowd sizes is called the Jacobs’ method. Herbert Jacobs was a journalism professor at the University of California, Berkeley in the 1960s. From his office window, Jacobs was able to see the campus’ main gathering plaza. And since it was UC Berkeley during the Vietnam War, there were a lot of protests.

Jacobs decided that, in order to count the number of people who attended these protests, he would overlay a grid on a picture of the plaza. From there, he counted the number of students in a few sections of the grid and used the average of those numbers to estimate the total crowd size.

It doesn’t take a scientist to realize that this method is lacking in, well, scientific methodology. Crowd density can vary, crowds can move, etc. etc. But just for kicks, let’s put this to the test:

Which grid boxes do you count?

Up to you!

How many do you need to get a reliable average?

As many or as few as you want.

So this is a flawed method?

Yes, of course.

And yet this semi-reliable guesstimate is still the method we rely on to this very day. The Jacobs’ method pervades because we still don’t have a widely accepted better method for counting crowds. Also, in case it wasn’t clear from the get-go, it’s not viable to just count everyone in a picture.

There’s actually a whole field of science behind crowd counting, with its very own dedicated scientists and computer programmers trying to put together a reliable method for counting crowds accurately and consistently. It isn’t quite nailed down yet, but it’s pretty good, if a little heady; let’s say it involves lasers and 3D satellite imagery, and leave it at that. The high tech option is there and if you’re willing to shoulder the expense to get a close to accurate count, it’s your best bet.

Here’s the thing though: The people who take the time to count crowds are motivated to exaggerate them.

Crowd numbers are typically released by the organizers of events. If crowd counters are just giving their best go of it when estimating crowd sizes because the scientific methodology either isn’t rigorous or isn’t accessible, then why would they ever underestimate?

That’s the real story here. Everyone exaggerates their crowd figures. Everyone does what they can to inflate those figures. Even in ticketed events, sometimes promoters will ‘paper the house‘, which just means they’re giving away free tickets to boost attendance numbers (the smart ones will make it like a freemium product, take a loss on tickets and make it back elsewhere, like in drinks).

And in the end, it’s mostly harmless. It is hilarious though when they get caught in their own hubris and even basic math can prove them wrong.

Take the most recent high profile crowd counting event, the Cubs’ victory parade (that’s the most recent right? I feel like I’m forgetting one…). The city of Chicago claimed 5 million people were there. That’s more than the population of Chicago. Even if you concede that there are more fans from outside the city, think about everyone you know. They don’t all care so much about baseball that they’d skip work and show up for the parade. And doesn’t Chicago have another baseball team, the White Sox? They probably have some fans too, probably ones that weren’t quite as enthused about the championship.

Next time you see an estimate of crowd sizes, just remember that that’s what it is, an estimate. Probably an exaggerated one. And sometimes it’s so exaggerated that it’s very easy to catch them in their lie.

P.S. The other way to effectively count unticketed crowds? Turnstiles. Like the ones in subways and metros (don’t know why that particular example popped into my head).