Organizers of Saturday's anti-war march in Portland are predicting it will draw a record turnout. The question is: How will we know?

Crowd estimates at protest marches have always been controversial, with organizers claiming that the police and media low-ball the number while cops and journalists counter that activists inflate the turnout.

The Jan. 18 march was typical. Organizers said there were 30,000 in the streets. The Associated Press pegged the number at 20,000. The police, tired of being second-guessed, didn't issue any estimate.

"The numbers have been plus or minus 5,000 for the local marches," says Will Seaman, one of the organizers of the January protest. "That says to me that no one has a way to do this properly."

Activists say there are ways to come up with accurate estimates: extrapolating overall crowd size from the number of people standing in a small area, say, or counting the number of marchers who pass a fixed point within a given period and then multiplying according to the march duration. But veteran activist Joe Keating says neither the police nor the press seems interested. "The Oregonian traditionally comes in at lower counts," he says. "It could be that they're just making an honest error. I think they don't like to make the event bigger than what they see in their mind's eye."

The paper's public editor, Dan Hortsch, says there's no hidden agenda but admits that it isn't exactly a science. Sometimes reporters make crowd estimates. Other times, they get police and organizers' numbers and print the range. "The numbers are a volatile issue," he says. "It's sort of a no-win situation."

In fact, both The New York Times and the Washington Post were chided by activists and media critics for using low estimates of marchers in January.

But Seaman concedes that activists aren't the most objective head-counters, either. "Even the most principled peace marcher is going to favor the higher numbers," he says.

Organizers of the March 15 protest are loath to make specific predictions, but given President Bush's war-talk, they agree that turnout will probably be massive. "We should probably break a record in a big way," says Dave Mazza, editor of the Portland Alliance, "as long as it's not dumping rain."