This was supposed to be the year, remember? The year that the East stood up and finally reached some kind of equality with the West. The year that 38-44 Eastern teams stopped grabbing playoff berths while 45-win teams out West went to the lottery.

Not so fast. Through Monday’s games, the East was a combined 63-90 in interconference play, making the Great Divide seem as big as ever. Five of the seven best records in basketball belong to Western teams. Even Portland, the worst team in the West, is nearly .500 (5-7) when it plays Eastern Conference opponents, while only five Eastern teams have winning records in interconference play. If not for mighty Detroit, the carnage would be even worse. The Pistons have gone 9-2 against the West thus far despite playing nine of the 11 games on the road.

For a local example, nothing signifies the East’s continued malaise more than the Nets. New Jersey has played hard about three times all season, yet right now they’re a game and a half ahead of the alleged competition for the East’s final playoff spot.

So what happened? Why hasn’t the East made up the ground we thought they would? Certainly, free agency can take part of the blame. If you look at this year’s free-agent disappointments, a disproportionate number of them are in the East. Metro areas fans won’t have any trouble identifying a few, such as Jerome James, Eddy Curry, and Jeff McInnis, but there’s plenty more where that came from:

* Antonio Daniels was supposed to help the Wizards make up for the loss of Larry Hughes, but he’s been awful thus far and lost his job to Jarvis Hayes.

* Bobby Simmons was supposed to be a major defensive upgrade for the Bucks, but he’s been surprisingly ineffective at both ends of the court.

* Boston blew its midlevel exception on Brian Scalabrine and Dan Dickau. Remember holiday shoppers, those 2-for-1 deals aren’t always as good as they seem.

* Philadelphia signed Phoenix’s Steven Hunter to bolster its frontcourt, but he lost his job to undrafted rookie Shavlik Randolph.

* And then there’s Joe Johnson, who Atlanta acquired in a sign-and-trade deal and paid superstar money to before realizing he’s not even remotely a superstar.

Overall, of the free agents who changed teams to sign in the East, only Chicago’s Darius Songaila has turned out better than expected, while many have turned out much, much worse.

The draft has helped the West, too. Only one rookie from this year’s crop has become an immediate star, and he plays out west. The emergence of the Hornets’ Chris Paul has turned an expected doormat into a fringe playoff contender at 11-13. Paul’s play has been so good that whether he’ll win Rookie of the Year is no longer the question – it’s whether he’ll make the All-Star team.

Yet even with those explanations, it’s hard to swallow how the East can be so far behind the West when our expectation at the start of the year was that the two leagues had drawn even. Clubs like Indiana, Cleveland, Miami, and New Jersey were supposed to be borderline title contenders. Certainly they were better than the Warriors, Clippers (!), Grizzlies, and Amare-less Suns … right? Guess again. Through Monday’s games, the latter group had the better record.

This turn of events leaves us scratching our heads, but there’s one simple cause that explains everything. You might want to sit down before reading it, because it pretty much overturns all our stereotypes about the style of play between the two conferences. Yet the evidence so far is almost impossible to ignore. So are you ready for a little secret? Here goes:

The East doesn’t play any defense.

That’s right. Our stereotype of tough, blue-collar Eastern teams slowing it down against run-and-gun, matadoring Western clubs has been laid to waste in 2005-06. Take a look at the leaders in Defensive Efficiency, my ranking of a team’s points allowed per 100 possessions. The top team, for the fourth year in a row, is San Antonio. Behind them are two other Western teams, Memphis and Phoenix. Yes, that Phoenix. The mediocre defensive club of a year ago has morphed into one of the league’s top defensive clubs.

In fact, of the top eight teams in Defensive Efficiency, seven hail from the Western Conference. Only the fourth-ranked Pacers break into the group, and they’re about to trade their best defensive player. Where’s Detroit, you ask? They’re 11th. In a shocking about-face, the Pistons have the best offense in the game but an average defense. It’s as though they exchanged rosters with the Suns and forget to tell everyone.

At the bottom, of course, it’s a different story. This is where you find most of the teams that were supposed to make the East a more competitive conference. The locals are there: the Nets rank 20th, the Knicks 23rd. So are Cleveland, at 24th, and Milwaukee, at 26th. Chicago, which was second a year ago, ranks 16th. You can find Washington (19th) and Philadelphia (22nd) down there too, along with usual suspects like Atlanta, Toronto, and Charlotte.

What might be the cause of the wide defensive disparity between the two conferences? Here’s one idea: Coaching. We thought the East was catching up because of its increasingly potent offensive talent, but we never looked at the guys on the sidelines. Check out the names out West: Popovich, Jackson, Dunleavy, Fratello, Van Gundy, Karl, D’Antoni. Smart, experienced men all, and every one has his team in the top 12 in Defensive Efficiency.

Compared to that list, the East still has a comparative lack of coaching acumen. The Knicks’ Larry Brown is in his first year in a tough job, as is Detroit’s Flip Saunders. And New Jersey’s Lawrence Frank, Cleveland’s Mike Brown, and Milwaukee’s Terry Stotts also are relative newbies. It’s no accident that the Pacers’ Rick Carlisle is the one Eastern coach with his team near the top of the defensive charts.

Add it all up and it’s no longer such a mystery why Eastern clubs are struggling while lightly-regarded Western clubs like the Clippers and Grizzlies have better records than 13 of the East’s 15 teams. Thanks to their players’ consistent efforts and their more experienced coaching staffs, the teams out West have been able to stop their opponents on a nightly basis, giving themselves a chance to win even when the shots aren’t falling.

If the East doesn’t rediscover its roots in tough, defensive basketball, it will be staring up at the West for a long time to come.

Mr. Hollinger is the author of the “2005-06 Pro Basketball Forecast.” He can be reached at jhollinger@nysun.com.