BOSTON (AP) – Experts in the imprecise field of measuring crowd sizes are scoffing at the city’s estimate that nearly 1 million people attended a recent victory parade for the New England Patriots, suggesting no more than 400,000 were on hand.

Academics expressed similar skepticism about the city’s estimate that 3.2 million fans turned out for the Boson Red Sox’ celebration last fall after their World Series win. They also questioned the official count indicating 800,000 pedestrians crossed Boston’s Zakim Bridge at its opening two years ago.

The new debate follows the Patriots’ Feb. 8 parade through city streets after the football team won its third Super Bowl in four years. City police acknowledged afterward that their estimate was based on guesswork.

The Boston Globe said Sunday that it asked two specialists to analyze photographs of the crowd and come up with their own estimates.

“It is hard to put more than 150,000 people along both sides of this parade route,” said Clark McPhail, a sociology professor at the University of Illinois.

McPhail wrote an award-winning book on crowds and helped the Washington Post count the 1997 Million Man March, which was said to be about 400,000.

“A million is a number that easily rolls off the tongue (but) it is much harder to mobilize that many people, even for a celebration,” he said.

The accepted method to estimate a crowd, he said, is to measure the size of the area, determine how much of it is occupied, then measure the density of the occupation.

Boston University professor Farouk El-Baz, director of the school’s Center for Remote Sensing, put the Patriot’s parade crowd at 400,000. He said the maximum capacity the entire 1.8-mile route could get only as high as 600,000, with people standing 50 deep along the entire route.

El-Baz, who analyzed U.S. Geological Society images of the parade, said he’s warned the media in the past that police or city estimates are faulty.

“The problem is you guys in the press,” he said. “We have several times suggested that when it comes to estimate of crowds, we cannot depend either on the organizers, who wish to make a very large political statement, or the police, who can either underestimate or overestimate depending on whether they support this thing or not.”