Steph Curry made the pull-up 3 the most important shot in the NBA

During Game 3 of their first-round series against the Portland Trail Blazers, the Golden State Warriors faced their first test en route to what they didn't yet know would be an undefeated run through the Western Conference playoffs.

The Warriors were holding a four-point lead with a minute remaining when rookie Patrick McCaw rebounded an Andre Iguodala miss. In the chaos of the offensive rebound, Portland wing Allen Crabbe ended up on two-time MVP Stephen Curry.

As he has done countless times, Curry isolated and used his dribble to get in shooting rhythm. Having created a small opening, Curry stepped back and knocked down a 3-pointer that effectively ended the game.

Even more so than the 3-pointer in general, the 3 off the dribble has been Curry's signature shot. And, with Curry's rise as Exhibit A, it might just be the most important shot in the modern NBA.

Modest efficiency, major importance

The funny thing about what I'm calling the most important shot in the NBA is it actually isn't a particularly good shot, in and of itself.

Not counting shooting fouls, the average shot attempt during the 2016-17 NBA regular season yielded a little more than one point -- 1.027, to be exact. (Half of this figure is what statistical analysts call "effective field-goal percentage," which is equivalent to the field goal percentage a player would have to shoot to score as many points with all 2-pointers as players do using both 2s and 3s.)

According to SportVU tracking on NBA.com/Stats, during the regular season players made what the site classifies as "pull-up" 3-pointers -- any 3 taken off the dribble -- at a 32.3 percent clip. Even after accounting for the extra value of the 3, that's still just .969 points per shot, about 5.6 percent worse than the average attempt.

When we talk about the high efficiency of 3-pointers, we're really talking about 3s of the catch-and-shoot variety-- those the NBA collectively made at an 36.9 percent rate this season, resulting in 1.111 points per shot.

Yet, as Kyle Wagner has noted on FiveThirtyEight, pull-up 3-pointers have increased dramatically in recent seasons -- even faster than the overall rise in 3-point rate. In 2013-14, the first season for which full SportVU data is available, 23.5 percent of 3-pointers were pull-ups. This season, almost exactly one in every four 3-point attempts (24.9 percent) came off the dribble.

So why are NBA teams taking so many more relatively low-value shots? For one, the pull-up 3 remains far more efficient than shooting a pull-up inside the arc. The league collectively made 2s listed as pull-ups at a 39.9 percent clip during the regular season, producing just 0.798 points per shot.

Additionally, it's easier to generate more pull-up 3s than it is to manufacture the superior open catch-and-shoot 3s, particularly against locked-in playoff defenses -- something Wagner pointed out could explain their rise in the postseason. The best pull-up 3-point shooters, like Curry -- who averaged 1.09 points per shot on them this season -- are capable of beating even good defense.

"We switched and switched, he really couldn't get anything off and he shot a great shot," said Blazers head coach Terry Stotts, referring to a Curry make in the first half of Game 3. "Sometimes, that's what great players do. For 95 percent of the league, that defense is going to be a miss."

Still, I think the value of the pull-up 3 lies less in the shot itself than what the threat of it sets up.

"Everything is a setup"

Portland point guard Damian Lillard, whose 445 pull-up 3-pointers since 2013-14 rank him third in the league over that span behind Curry and James Harden of the Houston Rockets, recalls learning the intricacy of pick-and-roll play from a trainer in 10th grade.

"He would always tell me, 'Everything is a setup,' " Lillard said.

The ability to shoot the pull-up 3 changes the way opponents defend pick-and-rolls and isolation plays, forcing them to come out higher to be able to contest a deep shot off the dribble. Lillard says he feels that difference on both ends of the court.

"You just know that you've got to be more in their space," he says of defending a player who can shoot the pull-up 3. "I know when a guy gives me space and I come off the pick-and-roll clean, that's a shot that I'm looking for because people want three points over two points now, especially with so many guys that can take and make that shot. So when I'm guarding a guy like that, I'm aware of it."

That newfound awareness of the need to crowd players who can shoot the 3-pointer off the dribble helps explain the exponential growth in fouls on 3-point attempts, as detailed recently by Tim Bontemps of the Washington Post.

Draymond Green, Curry's Golden State teammate and a finalist for defensive player of the year, points out that extending to defend a great shooter like Curry goes against the natural tendency for big men.

"Everything you're taught about basketball is to get back on defense and contain the paint," Green said after Curry's late 3-pointer against the Blazers. "You've got guys waiting on him at the 3-point line. Then he pulls up four or five steps outside the 3-point line? It's pretty impossible to guard."

Come out too far, and a defender will prevent the pull-up 3, but at the cost of getting beaten off the dribble.

"Then you start running out there at him and he gets in the paint and finishes," Green added. "You're kind of at his mercy when he's coming down like that. That's why that shot has become a common thing over the last few years -- because he can make it with consistency. As soon as guys start to run out there at him, he's going by them and getting to the rim and creating for other guys."

Demonstrating the power of the pull-up 3

A funny thing happens when you pull up -- pun intended -- the NBA's leaders in pull-up 3-pointers. The leaderboard doubles as a list of the league's top point guards.

Of the top 10 in pull-up 3s this season, seven were All-Stars. Chris Paul would have joined them in the All-Star Game if not for an injury. Lillard is a two-time All-Star, leavingMike Conley-- perhaps the best player in NBA history never to be an All-Star -- as the lone player in the top 10 without an All-Star appearance to his credit. Meanwhile, John Wall of the Washington Wizards was the only All-Star point guard who didn't make the top 10 in pull-up 3s. He ranked 37th in the league with 40 made 3s off the dribble.

The ability to hit the pull-up 3 is also associated with better performance in pick-and-roll situations. Here's how pull-up 3s compare to points per play as a pick-and-roll scorer or passer among players with at least 600 such plays, according to Synergy Sports tracking.

At the extreme, given no other information, we'd expect pull-up 3 leader Harden to average .15 more points per 100 pick-and-roll plays as a scorer or passer than Tony Parker of the San Antonio Spurs, who did not make a single pull-up 3 this season.

Intriguingly, this discrepancy persists even when you account for the pull-up 3s the player actually made and attempted -- not surprising given those aren't particularly efficient shots in and of themselves. That suggests the threat of the pull-up 3 is making these players more efficient as drivers and distributors.

Curry still the king of the pull-up 3

It was a down season from beyond the arc for Curry, whose percentage on pull-up 3s dropped from 42.0 and 42.8 percent during his MVP campaigns to 36.4 percent during the 2016-17 regular season, his lowest percentage during the four seasons for which SportVU tracking is available.

Still, over those four seasons, Curry has lapped the field:

Harden and Lillard are the two other players with half as many pull-up 3s over the past four seasons as Curry. And besides the Warriors, only six other teams in the league have made more pull-up 3s combined than Curry all by himself.

In the postseason, Curry is back to his old ways. He has made 2.4 pull-up 3s per game, according to NBA.com/Stats, hitting them at a 39.2 percent clip.

"It's definitely a huge weapon for us and he does it at key times, for sure," Green said after Game 3.

The biggest pull-up 3 attempt of Curry's career was a miss in the final minute of Game 7 of last year's NBA Finals when he was isolated against Cleveland Cavaliers forward Kevin Love. If a similar scenario plays out this year, this time the Cavaliers might experience the same feeling of helplessness the Blazers did.