There's no question they've improved. They're giving up tons of fewer points and taking the ball away more. Moreover, they aren't getting as much help from the Pats' offense (NE's offense is scoring less, moving the ball worse, and possessing the ball for shorter lengths of time, all of which put more pressure on the defense) as they were early on, and they've played against better offenses than they did the first 3 games. Those are all facts. It doesn't mean they suddenly can dominate against Pittsburgh or Indy. I suspect they're not yet ready for those challenges. But they *are* improving...there's really no objective way to deny that.