Glenn Beck rally attendance: calculating how many really showed up

Can we really get an accurate count of the number of people who attended Saturday's Glenn Beck “Restoring Honor” rally? The answer might be, “No, we can’t.”

Crowd-counting science is far from exact. Much of it is based on examination of overhead photos to calculate crowd density and related statistics. It reminds us of the old intelligence agency practice of “shedology,” in which the Central Intelligence Agency and others estimated Soviet weapons numbers by looking at overhead photos of military sheds and calculating how many tanks they might hold.

Plus, numbers are inevitably colored by an estimator’s interest. Rally organizers usually say crowds were huge, bigger than expected. Critics will say the numbers were less than anticipated. That’s been the case for years.

That’s led to controversy in the past. In October 1995, the National Park Service estimated that about 400,000 people attended the “Million Man March” organized by the Nation of Islam and Louis Farrakhan. Organizers were so angry they sent lawyers to meet with the Park Service.

Shortly thereafter, the Boston University Center for Remote Sensing estimated that the crowd had been 837,000, plus or minus 20 percent. What was the difference? The Park Service counted via pictures taken from videotape. The Center for Remote Sensing used original photo negatives.

Photos of the Beck event clearly show a big crowd. The weather was great – whatever the exact figure, there were a lot of people there. The area along the Reflecting Pool stretching out from the Lincoln Memorial was packed. Groups were gathered under trees far on either side. Large conglomerations of folks gathered all the way to the Washington Monument.

The crowd was big enough to disrupt Washington's subway system, with service from at least 12 stops disrupted due to long lines for entry.

Given that context, let’s wade into the numbers.

Rally organizers, in applying for their permit, said they expected a crowd of up to 300,000. And on Sunday, after the rally, Beck himself said on Fox News that the event drew 300,000 people on the low end, and perhaps as many as 650,000 people on the high end.

Rep. Michele Bachmann (R) of Minnesota, at her own rally held on the edges of Mr. Beck's event, said, “We’re not going to let anyone get away with saying there were less than a million here today because we were witnesses.”

However, a firm hired by CBS News to estimate the crowd put attendees at between 78,000 and 96,000. The firm, AirPhotosLive.com, had three estimators go over high-resolution aerial photos of the event, and then combined the three estimates. (One of the estimators talks about the experience here.)

These kinds of debates over crowd attendance go way back.

We’ll close with Joni Mitchell’s line: “By the time we got to Woodstock, we were half a million strong . . . "

Except they probably weren’t. Organizer Michael Lang later estimated the Woodstock crowd at about 400,000. Only half of those had tickets.