As always, we’re getting some new information and finding some errors, so after this morning’s first go-around, let’s take a second pass at estimating the number of people at yesterday’s rally by Glenn Beck at the Lincoln Memorial.

First of all, as commenter “Raymond Shaw” points out, the actual “dense crowd” number used by the National Park Service is five square feet per person, not ten. I missed a step by not explaining that I started using ten square feet in my original estimates last year to account for the difference in density between the really crowded areas near the front and the less dense areas near the back.

Estimate 10 square feet per person 5 square feet per person 2.5 square feet per person
Maximum: 215,000 people 430,000 860,000
90 percent 200,000 400,000 800,000
75 percent 163,000 326,000 652,000
50 percent 108,000 216,000 432,000
CBS News Estimate 87,000 87,000 87,000
40 percent 86,000 172,000 344,000

If we use those Park Service figures, obviously the estimates double or quadruple, as shown in the amended table above.

I continue to think those numbers are too dense. Five square feet per person means a space 24 inches deep by 30 inches wide; 2.5 square feet per person is one 12 inches by 30 inches.

Just to try to make sense of these intuitively, let’s consider standard towel sizes:

Towel type Dimensions Area
Bath sheet 35 in x 60 in 15 square feet
Beach towel 30 x 60 12.5 square feet
“Dense” crowd 24 x 30 5 square feet
Hand towel 16 x 30 3.3 square feet
“Packed” crowd 12 x 30 2.5 square feet
Wash towel 13 x 13 1.7 square feet

So the numbers quoted for the Park Service estimates come down to each person standing on a space a little more than a hand towel for the less dense number, and a bit more than a wash towel for the more dense.

Frankly, if I’m that close to another person for any length of time, I want dinner and a movie.

The pictures we have are apparently from fairly early in the rally, and as I say, I took the conservative approach by only counting what I could see.  We can speculate some, though, by guessing that some further number of people arrived and occupied areas outside my perimeter (more about that below) and use that to make some more estimates.  So let’s extend that, speculatively:

Speculative Estimate 10 square feet per person 5 square feet per person 2.5 square feet per person
150 percent 323,000 645,000 1,300,000
125 percent 269,000 538,000 1,076,000
110 percent 237,000 473,000 946,000
100 percent (was “maximum”) 215,000 people 430,000 860,000
CBS News Estimate 87,000 87,000 87,000

The one thing we can say for certain here is that the CBS News estimate looks more and more foolish.