A sea of angry taxpayers marched on the Capitol on Saturday afternoon. That much is certain. But even before the march was over, the news media, bloggers and rally supporters were wrangling over the crowd count, with estimates ranging from 60,000 to 2 million.
The Daily Mail in England initially reported that 1 million people flooded the west lawn of the Capitol, protesting what they called the dangerous big-government policies of President Obama. Some conservative blogs claimed 2 million attendees.
The two groups that sponsored the event offered more modest but widely varying numbers. Pete Sepp, a National Taxpayers Union spokesman, said the group estimated the crowd at 75,000 in the morning and from 200,000 and 300,000 as the day went on. FreedomWorks spokesman Adam Brandon put his "conservative" estimate at 600,000 to 800,000 after comparing photographs of Saturday's protest with previous events.
Although no official crowd estimates were issued, local officials and an expert indicated the number was more likely under 100,000, still a sizable turnout.
Farouk El-Baz, a Boston University research professor and expert on crowd estimation, said his informal research from press coverage indicated 75,000 as the peak number. Pete Piringer, a spokesman for the District of Columbia Fire Department, said he made an unofficial estimate of 60,000 to 70,000 at the beginning of the event.
Washington Metropolitan Area Transit Authority spokesman Steven Taubenkibel said Saturday that ridership figures indicated an extra 87,000 people took the subway all day, a significant increase over the 350,000 average.
Confusion and anger over crowd estimates are as much a part of Washington as its marble monuments. Organizers of the Million Man March in 1995 threatened to sue the National Park Service over its crowd estimate of 400,000, when their own number was 1.5 million to 2 million.
Boston University's Center for Remote Sensing estimated the Million Man March crowd at 837,214, with a 20% margin of error. The center, headed by El-Baz, used aerial photographs provided by the Park Service to do a computer analysis of the turnout.
Afterward, Congress directed the agency not to produce estimates.
"We do not give crowd estimates for any event, any time, whatsoever, period," said National Park Service spokesman Bill Line.
The controversy this weekend was fanned by the Internet. Bloggers circulated a photo showing a mass of people on the National Mall as evidence of a larger crowd. But it turned out the photo was taken at least five years ago: The National Museum of the American Indian, which opened in 2004, is not on the Mall in the picture.
El-Baz said the only accurate way to measure attendance is by counting heads in a photograph taken from an airplane or satellite, an expensive undertaking. No such photo was taken Saturday, to El-Baz's knowledge. Airspace over the National Mall is restricted.
"There is just no way for anybody [on the ground] to estimate the crowds," El-Baz said of people trying to do rough counts. "Most of these [other] numbers are not even in the ballpark."