NOT MANY NFL stats reflect how your offense and your defense are doing. Turnover differential does. It shows the difference between how much (or how little) your offense is screwing up and how much (or how little) damage your defense is inflicting on the other team.

Shockingly enough, the 4-8 Eagles are tied for last in the NFL in turnover differential, at minus-13, the worst figure of the Andy Reid era, in fact, the Birds' worst since the 1983 Marion Campbell season. The 22 interceptions their quarterbacks have surrendered are the worst figure in the league. With four games left, the 11 interceptions they have managed are less than half their 2010 total of 23 - and that was a defense that got its coordinator fired at the end of the season.

So, how come?

" 'Cuz we threw the ball to the other team," Eagles quarterback Michael Vick, who has 11 interceptions, explained yesterday, jokingly. "I know I've thrown a lot this season and wish I coulda had a couple of those throws back, but I still think I do a good job in taking pride in taking care of the football . . . I haven't lost confidence, still going to stay confident and keep playing hard."

Confidence is a factor in defensive turnovers as well, middle linebacker Jamar Chaney said.

"You gotta believe you're going to get turnovers. You got to have the confidence and the 'swag' that, 'OK, man, we're fixing to go out here, and we're fixing to dominate - we're going to get turnovers.' I'm pretty sure that's how Baltimore and the Steelers and those teams do it," Chaney said. "They expect to go out there and get three-and-out, or they're going to get the ball back [with a turnover].

"You can't just go out there and get the swagger. You've got to go out there on the field and perform and [earn] that confidence. You can say, 'We've got that swagger, we've got that confidence,' but until you actually go out there and execute on the field for a couple of games, [and] you know that teams can't do this or do that on you, we're going to make them one-dimensional - that's when that comes into effect. You can't just talk . . . you got to actually show that on film."

The other two teams at minus-13 are the Colts and the Redskins, two outfits everyone agrees have been afflicted with horrible quarterbacking this season. Have the Eagles had horrible quarterbacking this season? They did last Thursday in Seattle, when Vince Young threw four interceptions and gave them no chance to win; but in general? John Beck, Curtis Painter-level quarterbacking? Vick has been to four Pro Bowls, Young to two.

"Turnovers are going to happen," Vick said yesterday, reiterating the at-least-mildly-disquieting view he has expressed several times. "It's better to have one, rather than three or four. Usually that team doesn't win the game."

The Eagles' view has been that some of their turnovers have been fluky. Everybody remembers seeing the ball knocked out of Jason Avant's arms, Avant then flipping and accidentally bicycle-kicking the ball into Buffalo linebacker Nick Barnett's midsection, the turnover that sealed an Oct. 9 loss at Buffalo.

"Usually, we overcome 'em with big plays, or our defense gets more turnovers. But every year is different, and this is my first experience [like this]," Avant, an Eagle since 2006, said yesterday.

"We talked about that stat this morning," tight end Brent Celek said. "We've been doing terrible in the turnover category. It's something we've got to change."

Fluky only goes so far. Twenty-two interceptions? And only 11 from the Birds?

"You could have a guy chasing the ball and he knocks the ball out when the dude breaks away, one of his defensive linemen picks up the fumble, that ain't luck. That's the defensive lineman hustling to the ball," Chaney said. Inference being, that happens more with opponents than with the Eagles.

"The games that we have not turned the ball over, against good football teams, we've played very well and won the game," Eagles coach Andy Reid said yesterday.

In fact, the Eagles have played one game all season without a turnover, their best game of the season in all phases, the 34-7 victory over Dallas on Oct. 30.

"I think, around the league, you're seeing defenses that have started off slow, and as the season goes on, they're gaining experience and getting better," Reid said. "The offenses that are limiting the turnovers, and the teams with explosive offenses have been the ones winning games right now."

And why hasn't that been the case with the Eagles?

"There are several reasons, but I won't go into those. I think we're working on getting better with those," Reid said.

And how does Asante Samuel go from 16 picks in 2009-10 to two this year?

Samuel said the past few games, opponents just haven't thrown at him. Before that?

"We were top five [in turnover differential, at plus-9] last year, huh? What do you think the difference is?" Samuel asked. "You don't want to say it? I got no comment."

Samuel might have been referring to his previously expressed view of the "fantasy football" offseason, the Eagles acquiring high-profile corners Nnamdi Asomugha and Dominique Rodgers-Cromartie, then trying to meld them with Samuel in a hodgepodge of styles and talents. He also might have been referencing the ascension of offensive line coach Juan Castillo to defensive coordinator.

"It's been a crazy year so far," defensive end Trent Cole said. "A lot of things have happened."

Running back LeSean McCoy is one guy who can say he isn't to blame. Despite a career-high 215 rushing attempts, and another 42 receptions, McCoy hasn't lost a fumble this season. But he is familiar with the problem.

"The only thing I can say is just lack of concentration," McCoy said. "Not executing. That's the only thing you can say about it. It's kind of haunted us the whole year. And it's still doing it. It's frustrating, knowing the type of team we have, how good we could be, with the potential here. What's stopping us from that is turnovers and all the small things."