Almost as soon as Barack Obama was declared the winner of the Nov. 4 election, projections of how many people will huddle on the Capitol Mall to witness his inauguration as the nation’s 44th president started inflating faster than the federal deficit. Would 1 million, 3 million or even 6 million (or one out of every 11 Americans who voted for him) join the throng?
And if you suspect those high-end projections are laughable, wait until you see the post-inaugural arm-wrestling and nay-saying from partisans and pundits over the dimensions of the "official" count.
When it comes to accurately counting crowds, the slogan should be "No, we can't." In reality, estimating the size of crowds at mass public events is much more about public relations than a quest for truth. Whether the crowd is gathering for an anti-war protest, a sports team's victory parade, a golf tournament, a pope's outdoor Mass or the swearing-in of the most powerful man on Earth, organizational reputations and personal egos are ballooned or deflated by public perceptions of whether the crowd is surprisingly large or disappointingly small.
Washington has been the site of many such examples of political popularity arithmetic, with inauguration crowds being only one example. Supposedly, George W. Bush drew 400,000 in 2005 and Bill Clinton 800,000 in 1993, compared to the record crowd of 1.2 million for Lyndon Johnson in 1965. "Supposedly" in all cases because no one knows for sure.
The most public brawl over the size of a big Washington crowd occurred in 1995, when Park Police estimated that 400,000 people had gathered for Louis Farrakhan's Million Man March. After Farrakhan threatened to sue, Congress banned the Park Police from making crowd estimates. Almost as bitterly disputed were the crowd estimates from a 2003 antiwar demonstration in Washington, which drew between 30,000 and 500,000 protesters, depending on who was doing the estimating.
A method for mob measurement
Even absent publicity-driven pressures to hype the size of a public gathering, no crowd that doesn't go through a turnstile can be counted without some margin of error. (And as recent election recounts have proved, even counting something as simple as a stack of ballots can have a considerable margin of error.) But some fairly simple math can be used to make defensible estimates of crowd sizes.
The method goes back to the late 1960s and a University of California at Berkeley journalism professor named Herbert Jacobs, whose office was in a tower that overlooked the plaza where students frequently gathered to protest the Vietnam War. The plaza was marked with regular grid lines, which allowed Jacobs to see how many grid squares were filled with students and how many students on average packed into each grid.
After gathering data on numerous demonstrations, Jacobs came up with some rules of thumb that still are used today by those serious about crowd estimation. A loose crowd, one where each person is an arm's length from the body of his or her nearest neighbors, needs 10 square feet per person. A more tightly packed crowd fills 4.5 square feet per person. A truly scary mob of mosh-pit density would get about 2.5 square feet per person.
The trick, then, is to accurately measure the square feet in the total area occupied by the crowd and divide it by the appropriate figure, depending on assessment of crowd density. Thanks to aerial photos or mapping applications like Google Earth, even outdoor areas can be readily measured these days.
Miami's annual Calle Ocho street festival, billed as "the world's largest block party", is a prime example of a claimed "million-plus" crowd that can be estimated better using Jacobs' method. Early on, the organizers of the 23-block event, which sprawls along the main artery of the city's Little Havana district, trapped themselves into annual increases on crowd size, so that each subsequent festival could be advertised as bigger and better than the last. Finally it became apparent that two-thirds of the population of South Florida would have to be dancing the merengue and eating croquetas shoulder-to-shoulder for the puffery to be true. So the Miami Herald measured the square footage of the festival area and calculated that it could hold a maximum of 175,000. Even if the entire crowd was replaced by new revelers at midday, it would be way short of what the organizers still insist on claiming.
Crowd estimation vs. civic promotion
Another Miami crowd-counting opportunity came in 1987, when Pope John Paul II visited the city for the first time. City officials predicted 250,000 people would line the route the Popemobile would take. An hour or so before the parade, Miami police issued a press advisory that about 25,000 people were gathered along the route; afterward, police spokesmen tried to keep a straight face when they said the crowd was as high as 200,000. The Herald measured the length of the route and the width of the sidewalk areas, and tallied how deep the crowd was at each block along the three-mile route. The result: 40,000.
Parades are notorious for producing inflated crowd estimates. One of the longest-running crowd-counting fairy tales is the number of people who line the annual Rose Parade route in Pasadena. As far back as the 1930s, according to the Los Angeles Times, parade officials have been estimating the crowd as a million-plus. In the 1980s, a scientist for Pasadena's Jet Propulsion Laboratory calculated that the maximum possible crowd along the parade route and in the viewing stands was about 500,000. But the million-spectators figure continues to be blurted even today in breathless coverage of the parade.
So, ignoring such tiny details as how many cars and buses and Metro trains and outdoor toilets it would take to handle an inauguration crowd of whatever size, how many people could actually be there Tuesday? Is it possible for, say, 2 million people to gather to witness the promised beginning of change they can believe in?
In theory all 69.5 million Americans who voted for Obama could fit into the boundaries of the District of Columbia's 61.4 square miles of dry land with a relatively roomy 25 square feet each. They'd be standing on every rooftop and massed in all the streets, but Homeland Security does have to consider every eventuality.
(Actually, if you gave every person on Earth the "loose crowd" standard of 10 square feet each, you could get them all into Miami-Dade County at the tip of Florida — where some days it seems like they're already there. A calculation like that makes you realize there are relatively few humans on Earth, but also how much unoccupied land actually is necessary to supply each of us with shelter, food and water.)
Could 2 million jam into the mall?
Happily for the District of Columbia, the inauguration crowd certainly won't reach electoral landslide dimensions. But if people jam into the 81 acres of the National Mall between 1st and 14th Streets Northwest at a tight 5 square feet per person, about 700,000 could squeeze in. The open area around the Washington Monument between Constitution and Independence Avenues, back to 17th Street Northwest, could wedge in another 700,000 at the same density. And assuming a looser crowd far back from the inauguration stand on the steps of the Capitol, perhaps another half a million could be milling around in the Mall area in front of the Lincoln Memorial.
Therefore, it is at least physically possible to pack something approaching 2 million Americans into the 2.1-mile stretch between the Capitol steps and Lincoln's feet. Thanks to the daunting logistical realities of housing, feeding and transporting a mob of visitors that would be quadruple the district's actual population, chances are good that the actual crowd will be smaller than that. Only post-inaugural aerial photos will tell us for sure.
There's one last element to the myth-making that goes into a crowd count. Someday, as many people will claim to have been in the crowd witnessing Barack Obama's inauguration as now claim to have heard Jimi Hendrix play at Woodstock 40 years ago. People love to brag about being a live witness to history — even when they weren't.
Steve Doig is a professor at the Walter Cronkite School of Journalism and Mass Communication at Arizona State University. During a 20-year career as a reporter at the Miami Herald, where he specialized in data analysis, he did reality-based crowd-counting stories about festivals, political rallies, bowl parades and other events.