How Do You Count a Huge Crowd?

Step 1 of 5

Counting everyone is impossible.

People move, overlap and leave. Any count that takes an hour is counting a different crowd at the end than at the start.

Step 2 of 5

So you count one patch properly.

Pick a square you can genuinely count — ten people by ten people — and count it slowly and honestly. That number carries everything.

Step 3 of 5

Then you count squares instead of people.

How many of that square fit in the space? That is a measuring job, not a counting job, and it is far easier.

Step 4 of 5

Multiplying is the whole method.

People per square, times squares, equals people. It is one multiplication standing in for tens of thousands of counts.

Step 5 of 5

The error comes from the patch you chose.

Crowds are thicker at the front and thinner at the edges. Counting one dense square and multiplying gives a badly inflated answer.

Rival crowd counts at the same event often differ by a factor of three, and the argument is always about which patch was sampled.