“History is mostly guessing; the rest is prejudice.” —Will Durant

How do you count — or miscount — the crowd at a pro-life march? Taking the Jan. 13 Celebrate Life March in Denver as an example, let us count the ways.

## Method #1 — How to Count a Stationary Crowd

There's a science to this, but it's not rocket science. It's just a matter of multiplying area times density.

Area estimation is the easy part thanks to drones, digital maps and other tools. In the Google Earth image below, the shaded half-circle on the lawn roughly matches the perimeter of the crowd at Denver’s Celebrate Life March:

Density is a little trickier, but there are some solid rules of thumb to help. As Popular Mechanics explains, a man named Herbert Jacobs came up with this rule: “a light crowd has one person per 10 square feet, a dense crowd has one person per 4.5 square feet, and... mosh-pit density would have one person per 2.5 square feet.”

So multiplying area times density, there might have been between 3,000 and 6,000 people at this event on Saturday.

## Method #2 — How to Count a Moving Crowd

After the Denver crowd rallied at the Colorado state capitol, they marched through the heart of the city. Here’s a video clip:

It's always tougher to count a crowd when it’s moving, but this video is helpful. The four-minute clip captures about half of the march, which took about eight minutes to pass. Assuming that 300 people walked by each minute, that's a crowd size of 2,400 people. (If you come up with a different count after watching the video, feel free to post that in the comments below.)

## Method #3 — How to Count a Pro-Life Crowd

Then there’s the “make up a random number” method, which was used by a local news station after the March. Granted, it’s a lot quicker than the rarely-used “count ears and divide by two” method, but it doesn't seem to be quite as accurate:

You heard that right. As 9News reported, the crowd at the Celebrate Life March numbered in the “dozens.”

Keep this in mind when you start hearing media crowd estimates for the March for Life in Washington, the West Coast Walk for Life in San Francisco and all the other events throughout the nation this year.

And whether by the dozens or the thousands — keep marching, and keep the faith.