In another sign of the tight campaign, the Cook Political Report, which tracks congressional races, has upgraded its ranking of the race to a tossup.
"This doesn't mean that we're saying McNerney is going to win," said analyst Amy Walter at the Cook Report. "But it's close enough that we can no longer give Pombo the benefit of the doubt."
The Cook decision was unrelated to the poll because "it was an automated poll," Cook said, "and we're suspect of those."
Majority Watch project, a joint venture between Seattle-based Constituent Dynamics and RT Strategies of Washington, D.C., conducted the automated survey, polling 983 likely voters from Oct. 24 to 26. The poll has a margin of error of plus or minus 3 percentage points.
Results show that 48 percent favor McNerney compared with 46 percent for Pombo, which roughly mirrors results of internal polls released recently by the McNerney campaign and an environmental group.
Majority Watch released results Tuesday of more than 40 similar surveys in competitive congressional districts around the country. Pombo spokesman Brian Kennedy and several conventional California pollsters say automated polls are not as reliable as proven survey methods.
"I don't believe these results. We acknowledge that this has become a close race, but by no measure is Pombo behind," Kennedy said.
A McNerney campaign staff member said the poll shows that the bitter contest with its "dishonest lobbyist-funded attack ads" has hurt Pombo.
McNerney communications director Yoni Cohen also indicated that the Pombo campaign itself validated the automated poll results. "If Pombo had any better polling, he'd have released it by now," she said.
Conventional pollsters, who use people to call prospective survey participants, don't consider automated systems as reliable.
The five-minute automated survey deployed by Majority Watch in District 11 dials a household, and a respondent answers nine questions by pushing phone buttons.
Pollsters need to know who is answering in order to obtain a statistically representative sample of the population, such as the ratio of men to women or Republicans to Democrats.
"The most respected pollsters don't consider this method to be as reliable," said Phil Trounstine, director of the Survey and Policy Research Institute at San Jose State. "Because it's an automated call, there's no way to know who is on the other end of the line."
To resolve the issue, Majority Watch polls ask respondents two validation questions age and gender which it matches to the voter-identification database, Constituent Dynamics spokesman Chris Bushnell said.
"Automated polling has been around a long time," Bushnell said. "I'm not saying our method is perfect, but we have a good track record, and we think we have done a good job."
Regardless of accuracy, the poll results reflect the latest views of the Cook Political Report.
Two months ago, Walter gave scant hope to McNerney, who had little money and no party support. Pombo, meanwhile, had some baggage but plenty of money, the power of incumbency and a party registration advantage.
"Today, the only thing that hasn't changed in that scenario is the party registration," Walter said. "It's not a normal year. Heck, Ben Affleck is going to campaign in (District) 11. Is that normal?"
Indeed, McNerney has attracted a groundswell of party support as Democrats flood into the district to campaign as the party works to take control of Congress.
National organizations are spending tens of thousands of dollars. Actors Affleck and Jennifer Garner have promised to walk precincts for the Defenders of Wildlife on Saturday.
Contact Lisa Vorderbrueggen at (925) 945-4773 or firstname.lastname@example.org.