When we discuss the reasons for the Atlanta Hawks’ success this season, we tend to speak in generalities.

“They bought into the system.”

“They play so unselfishly.”

“They move the ball well.”

All of these statements are true, but they don’t necessarily help us understand the transformation Atlanta has made into becoming a legitimate NBA title contender.

The truth is, Atlanta isn’t all that different on offense from what it was a season ago in terms of making the extra pass. The Hawks average just 0.8 assists per game more than they did in 2013–14, and they average fewer than three more passes per game in total:

Also, for as unselfish as the Hawks have been with moving the ball, it’s no sure thing in today’s NBA that more passes leads to better offense.

In fact, the two teams leading the NBA in passes per game are the Utah Jazz and New York Knicks. Utah averages 45 more passes per game than Atlanta, but has just the league’s 15th most efficient offense. As you can see, the top seven passing teams all vary wildly with degrees of success.

Passing generally leads to better shots. However, when the passing lacks clear purpose, it simply winds the shot clock down and forces players to beat the clock with attempts outside of their comfort zones.

Watch below as the Jazz make five passes in 14 seconds but fail to find a better shot than a Trevor Booker floater from the foul line:

So while Atlanta is one of the NBA’s best passing teams, that’s not the lone reason the Hawks have been dominant. So, what gives? How has Atlanta surged into an offensive powerhouse?

I’ve been investigating that question all season, and have gained a pretty strong grasp on what’s made them click. There are two analytical secrets to Atlanta’s success that the Hawks have exploited, and the results have transformed them from middling East pesterer into a powerhouse.

1. Gaming the margins with shot type

Clearly, not all shots are created equal, but how much variability in quality is there in shot type?

I’ve tracked the 70,000+ jump shot attempts (outside of 12 feet from the basket) from the 2014–2015 season, and detailed the advantage of field goal attempts out of a catch-and-shoot situation rather than a pull-up.

While the percentage differences may seem negligible, make no mistake: the advantage that comes from catch-and-shoots is big enough to decide outcomes in games. Atlanta lost 13 times by five points or less last season.

The data from last season and this one suggest that Atlanta surely is aware of the shot-type advantage (or, in this case as shown below, disadvantage) and has made a concentrated effort to reduce its pull-up shot attempts.

As you can see, the Hawks have cut back on their pull-up attempts, reapportioning nearly all of those possessions into six extra drive attempts per game. Again, these numbers may appear marginal, but they’re actually drastic. Atlanta went from taking the fifth-most pull-ups in 2013–14 to tying for the least so far in 2014–15. No other team has come close to Atlanta’s dropoff of 3.9 pull-up attempts per game from season-to-season:

With approximately four extra possessions saved from lower efficiency shots, Atlanta has concentrated on infiltrating the interior off the dribble. Currently, Atlanta is attempting 6.4 more drives per game than last year.

What’s interesting is that while most teams experience lower efficiency rates with increased attempts, Atlanta has actually become a more efficient driving team this season — improving their 41.9 percent drive conversion rate (25th ranked in 2013–14) to a 46.1 percent clip (14th ranked in 2014–15).

This can best be explained by Dennis Schroder’s emergence as one of the league’s most prolific drivers. Schroder is the only player in the league who plays less than 20 minutes per game yet still has attempted more than 350 drives for the season. He also converts his drives (48.8 percent) at a higher rate than All-Stars Kyrie Irving, Jeff Teague and Russell Westbrook.

But Atlanta’s gains from driving are multifaceted. For every drive to the hoop, there’s a primary focus to finish with a layup or dunk, a secondary desire to draw a foul (Atlanta has jumped from drawing the 20th-most fouls in the league last season to the 12th most this season) and a tertiary intention to force the opposing defense into converging at the paint — creating openings for shooters on the perimeter:

Atlanta attempts the most catch-and-shoots per game in the entire league, tied with Portland and Indiana at 29.9 per game:

Only Houston attempts more catch-and-shoots from the perimeter, but the Rockets convert at a much lower rate than Atlanta. Personnel is key here: led by Kyle Korver, the Hawks are on pace to be the league’s only team to shoot better than 40 percent from deep on catch-and-shoots.

Make no mistake, leading the league in catch-and-shoots while attempting the league’s fewest pull-ups does not happen coincidentally. It’s a calculated decision to infuse the gameplan with higher efficiency shots. Head coach Mike Budenholzer probably recognizes this, but won’t let on with the media:

“I don’t know if it’s a strategy,” said Budenholzer. “We want to attack the rim and score there first. We want to have spacing around our rim and paint attack. So it probably lends itself a bit to more points at the basket. And if it’s taken away, we move the ball for catch-and-shoot opportunities. Our personnel is built that way, so I don’t know if it’s totally by design. I think a lot of things kind of just go that way.”

It’s important to clarify that if the strategy isn’t totally intentional, having their roster built this particular way is. One Eastern Conference scout familiar with Atlanta’s front office — speaking on the condition of anonymity — believes the team traded pull-up happy Lou Williams to Toronto over the summer precisely to replace his minutes with better defenders who have better catch-and-shoot tendencies (i.e. Thabo Sefolosha and Kent Bazemore).

“Pull-ups are an Iso-game,” said Paul Millsap. “We’re not an Iso-team. We’re a drive, kick-out to a teammate, catch-and-shoot or drive, bring it in to a big to lay it in type of team.”

But for as analytically sound as Atlanta’s offense has become, it’s really the team’s defense that has made the Hawks the powerhouse they’ve become. Much in the same way critics are skeptical about whether the team can win a championship without a true “go-to” superstar, they also are wondering whether Atlanta can maintain its elite defense without a true rim protector.

Here’s Atlanta’s secret on defense:

2. Ignore the offensive glass to prevent early opportunities for opponents

Budenholzer’s defense has thrived thanks in part to a strategy that would have been admonished by the basketball community not so long ago. To put it simply, the Hawks largely ignore offensive rebounding opportunities. Atlanta ranks last in the NBA in both offensive rebounds (8.3 per game) and offensive rebounding rate (20.6 percent). (For reference, the Hawks are 21st in defensive rebounding percentage, per TeamRankings.com.)

Ignoring offensive rebounds is a crucial element to Budenholzer’s defensive strategy. Because the Hawks shoot the ball at such a high efficiency, they’re willing to sacrifice potential extra possessions from offensive rebounds if it means they can limit easy scores in transition for opponents. After all, transition opportunities lead to some of the easiest points in the NBA:

Watch in this video as Paul Millsap concedes potentially strong positioning for the offensive rebound to quickly run back on defense:

Atlanta ranks second in the NBA in transition defense, allowing just 2.52 points per 100 possessions in beat-back-on-defense situations.

So, what does that mean exactly? In comparing that number with Cleveland’s 4.01 points per 100 possessions in beat-back situations and adjusting to account for possessions per game, Atlanta’s approach translates to a 1.34-point defensive advantage. In other words, against Cleveland, Atlanta’s essentially starting the game with 1.34 free points on the board.

Atlanta’s found holes in conventional defensive strategy and has tailored its game plan to correct those holes. The subtlety behind the advantage masks the reality that Atlanta is outsmarting opponents by anticipating and preventing fast breaks before they happen — or as Budenholzer would say, “controlling what’s controllable.”

“Getting back’s our biggest thing,” said Jeff Teague. “We’re trying to limit opponent’s transition points. We want to make them play against our half-court defense, and if we can do that, we feel like we have a pretty good chance.”

By forcing opponents into finding shots in a half court setting, Atlanta is directly using the shot clock as a sixth defender on the floor. As teams have to labor through the shot clock to find a good shot opportunity, the average field goal percentage drops dramatically:

Graph via TheNylonCalculus.com

It’s an analytically-savvy strategy that very few teams employ.

Sacrificing offensive rebounds for the sake of limiting fast break opportunities has slowly gained traction around the league but the Hawks remain the most aggressive of all. As for why Atlanta’s defense has improved so dramatically this season (besides the obvious benefit of having a healthy Horford back on the floor and the welcomed additions of Sefolosha and Bazemore), the players attribute their defensive success with increased familiarity to the game plan.

When Demarre Carroll signed with the Hawks, his most notable talent was his offensive rebounding prowess as a wing player. This season, he’s finally comfortable forfeiting what had always been his biggest strength:

“It was kind of hard,” Carroll admits now. “When I got here last year, I was kind of resistant about it. But this year I think Coach lets me pick and choose (when to crash). And since I am guarding the best player on the other team, I just try to get back.”

Even for non-offensive rebounders like Korver, the idea of surrendering the offensive glass seemed puzzling initially:

“It was tough to give up,” Korver said. “And I’m not even a big offensive rebounder. I probably had like 10 in my career. But still, you don’t really think about sprinting back on defense. Luckily, I came from Chicago with Thibs, where he was crazy about it. I mean, if I even took a step towards the basket (for an offensive rebound), I was getting yelled at. For me, it maybe wasn’t as big of a deal. For a lot of guys, it’s about opportunity. You’re taught that playing hard means going for the offensive boards and trying to get an extra possession. For a lot of guys, it is tough to give up on.

“You think, ‘maybe the ball will get tipped out to you and you’re going to get a three.’ And you know, anytime you think you have an opportunity you try to take advantage of it. But this is what our defense is predicated on first: not giving up points in transition. That’s our first major key, and I think we’re doing a pretty good job.”

Millsap, who ranked in the top five in the NBA for offensive rebounding early in his career, has come around to see the personal benefits of ignoring the battle for offensive boards:

“By getting back, you’re actually helping yourself with wear-and-tear and conditioning-wise,” said Millsap. “There are times when you want to get down there and get the extra possession. That’s where I came from. That’s who I was before.”

Millsap still leads Atlanta with 1.7 offensive rebounds per game — but it’s a far cry from the 3.3 he averaged early in his career with Utah. Still, as Millsap pointed out, to say he’s sacrificed offensive rebounds completely may be an exaggeration.

“It’s not really completely, especially for the bigs. The bigs have some freedom. But you have to sacrifice something. If you want to be a defensive transition team, you have to give up on offensive rebounds and get back.”

When we hear the media talk about Atlanta’s players “buying into the system,” they point to the ball movement on offense. In actuality, Millsap’s quote above is the best possible example of a player buying into the system.

Millsap used to love (and thrive individually) battling for offensive boards. Now he’s not only willing to surrender those battles: he genuinely understands his team is better off because he does surrender those battles.

Budenholzer has implemented a strategic revolution. Now his players have bought in, and are dominating the league through its application.