Consumer Reports defends the dunce cap it gives Chrysler in the publication’s latest auto maker “report cards,” despite significant gaps in survey data used to generate its influential ratings.

The publication says Chrysler is “last in the class” for performance, comfort, utility and reliability – attributes measured with comprehensive road tests and a predicted reliability score derived from an annual reader survey.

Survey data is worth 50% of an auto maker’s grade and covers three model years. But the publication had no data for 16 ’10 Chrysler vehicles and 10 ’09 products.

David Champion, senior director of Consumer Reports’ auto test division, admits his group’s Chrysler data was “scarce” for some model years. But he warns data is a double-edged sword and might have painted an even grimmer picture.

“It could help or it could hinder (Chrysler’s rating); reliability may drop even further,” Champion tells Ward’s.

Dealers are not surprised by the low marks. “We’ve always felt, as Chrysler dealers, like Consumer Reports has never given us a fair shake,” says Chuck Eddy, owner of Bob and Chuck Eddy Chrysler Dodge Jeep and Ram in Austintown, OH.

“They don’t open the book completely,” says Eddy, who also sits on Chrysler’s national dealer board.

Chrysler quality chief Doug Betts is disappointed, but unfazed by the publication’s “conservative approach” to analysis.

“We know how the Consumer Reports system works,” he tells Ward’s in an e-mail. “If I was in their business, I’d take the same approach. Unfortunately it drives a delay in recognition of our improvement.”

In a statement, Chrysler calls the publication’s data “insufficient” because it is heavily weighted on the ’08 model-year. And the auto maker has said previously its warranty claims have declined dramatically since then.

Consumer Reports invites its readers to participate in its annual survey. This year, more than 1 million people did so, Champion says.

But such research practices are problematic, warns Philip Stark, a professor of statistics at the University of California, Berkeley.

“Those people who do participate typically are not representative (of a population) because they have reasons for participating,” Stark tells Ward’s.

“You’re going to tend to get people who love their cars or hate their cars. They’re either really happy and want to rave about their cars or they’re really (angry) and want a chance to gripe about it in public.”

Even if the publication compiled a random sample that was statistically valid, there still would be pitfalls.

“Their readers are not necessarily representative of car owners in general,” Stark says. “Despite the fact that they’re so numerous, they’re the kind of people who read Consumer Reports. And a lot of people don’t.”

Returning year-after-year to a pool of readers accustomed to seeing recommendations for auto makers such as Honda, this year’s top performer, also can skew a sample. “It actually hurts us in some ways,” Champion admits.

Stark, who had not seen the magazine’s methodology, tells Ward’s he is less concerned about gaps in model-year data. If the vehicles considered are high-volume, “maybe that is representative of what people typically buying Chrysler would get,” he says.

In its latest issue, Consumer Reports recommends a single Chrysler product that also happens to be its best-seller, the Ram fullsize pickup.

Betts is optimistic the auto maker’s performance will improve when Consumer Reports conducts its next survey. That’s because ’08 data will fall off the table.

“We’re confident that the 2011 cars that we’re currently launching will be well-received, even by Consumer Reports subscribers, and the (data gap) issue will be rectified this year,” he says in his e-mail.

Key quality-improvement initiatives show promise. Among them is a partnership with Roush.

Adapting test procedures employed by Chrysler alliance-partner Fiat, Roush employees subject production vehicles to thousands of additional miles of real-world use in five disparate U.S. climate zones.

Based on his behind-the-wheel experience, Champion says Chrysler vehicles are “headed in the right direction.”

In less than two years, the auto maker has introduced 16 new or significantly refreshed vehicles.

Eddy predicts the auto maker will catch up with itself within 12 months. Then he hopes to see upbeat headlines associated with Consumer Reports.

Consumer Reports is very respected,” he says. “If we didn’t care about it, we wouldn’t want them for a third-party endorsement. I really would cherish the day that Consumer Reports says, ‘Chrysler is a viable product; go buy it.’”

But Champion offers no guarantees. Other auto makers also are improving, he says, noting half of the survey respondents reported no problems with their vehicles.

“You’re chasing a moving target,” he warns.

Joining Honda at the top of the Consumer Reports class are Subaru and Toyota, placing one-two-three for the third consecutive year.

Mercedes-Benz and BMW receives the lowest grades, after Chrysler, which recorded 94,636 light-vehicle sales in February for a 12.4% jump from year-ago, according to Ward’s data.

Through 2011, Chrysler sales are tracking 17% ahead of like-2010 on the strength of the Ram pickup and new-for-’11 Jeep Grand Cherokee midsize SUV.