If you asked most casual basketball fans to name the four teams with the most wins in the NBA, they would likely get at least three right. If, though, you were to ask them who has the fifth most victories, I would bet that a large majority would get the answer wrong. It's the Houston Rockets, and they are easily the quietest success in the league right now. They are winning with surprising regularity - 16 times in their last 21 games - and they have done it despite playing without Tracy McGrady over that stretch. So how are they doing it? Here's a look:

Defense - The biggest reason we don't hear a lot about this team compared to others is that they focus on defense, and defense is boring. The Rockets aren't even one of those ruthlessly effective defensive teams that get attention by topping the statistical categories and winning awards. They just consistently work hard when they don't have the ball, and they regularly allow few enough points that their underwhelming offense is still able to score more. That leads to wins. Ron Artest is obviously the biggest defensive name on the team, and he is playing better than many probably expected him to at this point in his career. Shane Battier is a very underrated defensive talent. Yao Ming can be made to look like a fool when he is matched up against someone smaller and agile, but he is near the top of the league in blocks, and he compares favorably defensively to most really big men in the league. In short, the team has taken reasonable talent, paired it with commitment, and they are seeing the rewards. That makes this a far more dangerous team in my eyes than one that relies on scoring a lot of points - defense depends most on effort, so it isn't nearly as prone to slumps.

Coaching - I'm torn on Rick Adelman. He's a truly lousy playoff coach that has managed to take a decent amount of talent absolutely nowhere in his career. In the regular season, though, he measures up favorably against most coaches when it comes to getting the most out of the talent he has. He has the Rockets playing better than they probably should be based on what they have on paper. That's no fluke - he hasn't led a team to a record below .500 since 1997, and that was in Golden State so it was hardly his fault. Aside from the playoffs, Adelman is a steadying, consistent force. His teams never overwhelm, but they rarely disappoint, either. I have a lot more faith in this Adelman team than I do in other contenders and their leadership.

Yao Ming - Yao might not be the megastar game changer that he was promised to be when he was drafted, but he has certainly evolved into a good player and a good NBA citizen. There is one stat that jumps out to me that typifies his contribution to this team - he has scored 30 or more points seven different times this season, and the team is 7-0 in those games. If I have a knock against the big man it's that he doesn't play enough minutes - he's averaging just 33 this year. Still, he's leading the team in points, rebounds, field goal percentage, and blocks, so you can't really complain too much. Yao is the face of this team outside the locker room, and it has become increasingly clear that he is growing into the same role inside, too. I'm not sure I would chose Yao if I was starting a new team, but he's certainly nothing but an asset for the Rockets, and a big part for their current success. It's also key to note that Yao has statistically elevated his game recently - he's playing better when the team needs it most. That's obviously a good sign.

Luis Scola - Luis Scola is getting an increasing amount of attention, but if he were in a more visible market he would be emerging as a star. The Argentinian has come a long way statistically in just his second season in the league - he has 29 double-doubles, including three in his last five games. His biggest impact, though, comes in the challenges he presents opposing defenses. If teams decide to focus on Yao to limit his rebounding opportunities, Scola swoops in and wreaks havoc on the boards. If the team needs scoring he can be good for 20 or more points. He's impressively good at dishing out assists for a power forward his size. Most striking of all, though, is his effort level. Scola is always the hardest working guy on the court, and his grinding effort rubs off on those around him (and annoys those playing against him). Scola isn't the MVP of thus team according to stats, but he may be the most important piece of the puzzle right now.

Division - Not to take anything away from Houston, but part of their success has to be attributed to the relative weakness of their division. The Southwest is still probably the most loaded and competitive group in the league, but the Spurs, Hornets and Mavericks are all not quite as sharp as they were last year. They are still good, but just not as good as they were. That has softened things up a bit for the Rockets, and has made it easier for them to do well. They had a slightly better winning percentage last year than they do this year, but last season they would up locked in third, while this year they are in a fight for the top spot.