By Stephen Shea, Ph.D.
February 25, 2016
Something special is happening in Portland. Amidst all the hoopla around Golden State, San Antonio, the impressive rookie performances of Towns and others, the impending free agency of Durant, trade deadline rumors, Cleveland’s coach, and Blake Griffin’s fist, that something special is going largely unnoticed.
Last offseason, Portland lost (through free agency) or traded 4/5 of its starting lineup. They lost LaMarcus Aldridge, Wesley Matthews, Nicolas Batum, and Robin Lopez.
Aldridge’s decision not to return was the catalyst for some of the other moves. This was a team that lost 4-1 in the first round of the playoffs with Aldridge. It made little sense to clog the cap with players like Matthews and Lopez while returning a team that projected to be less competitive.
Portland wisely chose the route of a major reconstruction. The team got younger. Among the top 10 in minutes played for Portland this season, only one player (Gerald Henderson) is over the age of 25.
The team cleared a ton of cap space. Lillard is signed to a massive extension, but beyond that, the team has a number of reasonable and modest contracts. Al-Farouq Aminu and Ed Davis are signed to decreasing contracts. They’ll be owed about 14 million total next season, and less than that the year after. Vonleh, McCollum, Plumlee, Leonard, and others are all still on rookie contracts (although a few are headed for restricted free-agency). Portland projects to be able to bring back their promising young core while still having tons of cap space in the upcoming offseason. (See http://www.basketballinsiders.com/portland-trail-blazers-team-salary/ for more details on Portland’s cap situation.)
Getting younger and clearing loads of cap space has all the markings of a complete rebuild, but I won’t call it that. In today’s NBA, a team that properly assesses talent, constructs intelligent lineups, and implements good offensive and defensive schemes can remain competitive through the process. Portland understands all of this. They are reconstructing, not rebuilding, and it’s impressive.
Defensive System
When a team replaces four starters, including a few exceptional defenders, you expect their defense to take a hit. When you replace experienced starters with a lot of youth, you expect the defense to take a big hit. When you lose defenders like Lopez and Aldridge and insert a 20-year-old Noah Vonleh, you expect the defense to plummet.
Portland’s defensive rating did go down this season. It dropped from 101.4 in 2015 to 104.3. (Although, they’ve had a DRtg of 101.8 in their last 18 games.) They are ranked 18th overall in the NBA this season. That’s not bad all things considered. For comparison, the Wizard’s dropped from a defensive rating of 100.0 in 2015 to a rating of 104.3 this season, and they largely returned the same core of players.
The Bucks dropped from 99.3 to 105.3 when they spent the offseason trying to build on what they had accomplished, not blow it up.
Portland is still above New Orleans, when New Orleans has the luxury of building around Anthony Davis in his prime (and also brought back largely the same core as a year ago.)
So, how does Portland do it? When we dig beneath the usual defensive stats, interesting trends emerge.
Previously, we introduced “painfully ill-advised shots” (PIS). These are contested pull-up mid-range jump shots that are taken with at least 5 seconds on the shot clock. These are not good shots, and it’s hard to justify a team or player’s choice to ever take a PIS.
We let PIS selection or PISS be the player or team’s percentage of shots taken with at least 5 seconds on the shot clock that are PIS. So, if a player had a PISS of 10%, 1 in 10 of that player’s shots with at least 5 seconds on the shot clock were PIS.
It turns out that some defenses induce more PISS than others.
The table below presents the opponent PISS and opponent PIS FG% for all NBA teams in each of the last two seasons. Opponent PISS ranges from 13.1% for the 2015 Trail Blazers to 5.6% for the 2014 Heat.
| Season | TeamName | Opp. PISS | Opp. PIS FG% |
|---|---|---|---|
| 2015 | Portland Trailblazers | 13.1% | 40.7% |
| 2014 | San Antonio Spurs | 12.3% | 39.0% |
| 2014 | Chicago Bulls | 11.9% | 37.1% |
| 2014 | Indiana Pacers | 11.8% | 38.2% |
| 2015 | Chicago Bulls | 11.3% | 40.6% |
| 2015 | Charlotte Hornets | 10.8% | 38.5% |
| 2015 | Indiana Pacers | 10.6% | 37.8% |
| 2014 | Portland Trailblazers | 10.5% | 38.5% |
| 2015 | Memphis Grizzlies | 10.4% | 39.5% |
| 2015 | Golden State Warriors | 10.3% | 37.7% |
| 2014 | Orlando Magic | 10.2% | 39.4% |
| 2014 | Golden State Warriors | 10.1% | 32.9% |
| 2015 | Washington Wizards | 9.9% | 37.5% |
| 2015 | San Antonio Spurs | 9.7% | 37.2% |
| 2015 | Boston Celtics | 9.4% | 37.1% |
| 2015 | Utah Jazz | 9.4% | 39.4% |
| 2014 | Charlotte Bobcats | 9.4% | 44.8% |
| 2014 | Boston Celtics | 9.3% | 39.5% |
| 2014 | Memphis Grizzlies | 9.1% | 37.7% |
| 2015 | Phoenix Suns | 9.1% | 32.5% |
| 2014 | Atlanta Hawks | 9.0% | 36.5% |
| 2014 | Denver Nuggets | 8.9% | 41.3% |
| 2015 | Sacramento Kings | 8.7% | 38.3% |
| 2014 | Los Angeles Clippers | 8.7% | 36.2% |
| 2015 | Los Angeles Clippers | 8.6% | 37.4% |
| 2015 | New York Knicks | 8.6% | 36.6% |
| 2015 | Orlando Magic | 8.6% | 39.7% |
| 2015 | Denver Nuggets | 8.6% | 41.6% |
| 2015 | Detroit Pistons | 8.6% | 38.0% |
| 2014 | Sacramento Kings | 8.5% | 34.4% |
| 2014 | Los Angeles Lakers | 8.5% | 34.9% |
| 2015 | Cleveland Cavaliers | 8.4% | 39.1% |
| 2015 | Atlanta Hawks | 8.3% | 40.3% |
| 2014 | Minnesota Timberwolves | 8.3% | 39.8% |
| 2015 | Dallas Mavericks | 8.2% | 35.3% |
| 2015 | New Orleans Pelicans | 8.2% | 36.0% |
| 2014 | Toronto Raptors | 8.1% | 36.1% |
| 2015 | Los Angeles Lakers | 8.1% | 38.0% |
| 2014 | Washington Wizards | 8.1% | 36.7% |
| 2015 | Miami Heat | 8.0% | 37.6% |
| 2015 | Toronto Raptors | 7.9% | 41.5% |
| 2014 | Phoenix Suns | 7.9% | 36.1% |
| 2015 | Minnesota Timberwolves | 7.7% | 39.7% |
| 2014 | Utah Jazz | 7.7% | 36.7% |
| 2014 | Cleveland Cavaliers | 7.7% | 33.2% |
| 2015 | Milwaukee Bucks | 7.6% | 34.6% |
| 2014 | Houston Rockets | 7.5% | 37.2% |
| 2014 | Dallas Mavericks | 7.4% | 37.5% |
| 2014 | Brooklyn Nets | 7.4% | 36.2% |
| 2015 | Brooklyn Nets | 7.3% | 35.2% |
| 2014 | Detroit Pistons | 7.2% | 39.1% |
| 2015 | Houston Rockets | 7.2% | 39.8% |
| 2014 | Philadelphia 76ers | 7.1% | 37.4% |
| 2014 | New Orleans Pelicans | 7.1% | 35.1% |
| 2014 | Milwaukee Bucks | 6.7% | 39.8% |
| 2015 | Oklahoma City Thunder | 6.6% | 42.0% |
| 2015 | Philadelphia 76ers | 6.6% | 39.6% |
| 2014 | Oklahoma City Thunder | 6.2% | 37.7% |
| 2014 | New York Knicks | 6.2% | 35.2% |
| 2014 | Miami Heat | 5.6% | 36.8% |
The chart below shows that in 2015, the Portland Trail Blazers were nearly 2 percentage points better in this category than any other team. This success is nothing new for Portland. They were 4th in the NBA in 2014. Playing Portland seems to have the same effect as chugging a large coffee and sinking your hand in a bucket of warm water.
Portland’s consistent PISS-inducing defense provides some evidence that defenses can actually influence their opponents’ shot selection. Note that if opponent PISS varied greatly from year to year, it would suggest that the statistic is unpredictable and largely out of a team’s control.
The year-to-year stability exhibited by Portland was not an anomaly. The chart below plots a team’s 2014 opponent PISS to their 2015 opponent PISS. The teams that were better at forcing PISS in 2014 tended to be better at the task in 2015.
How does a team induce PISS? Is it personnel dependent?
Inducing PISS is less about the perimeter defender’s ability and more about the team’s system and the interior defenders. In 2015, the top two in opponent PISS were Steve Blake (27.8%) and Damian Lillard (27.0%). Both played for Portland. Two of the next three in opponent PISS played for Chicago (Aaron Brooks and Derrick Rose). Two other Chicago guards, Tony Snell and Kirk Hinrich, were in the top 20. (Tom Thibodeau was the NBA’s catheter.) San Antonio’s two point guards Tony Parker and Cory Joseph were 7th and 8th with nearly identical opponent PISS. (In 2014, Parker and Patty Mills were both in the top 5.)
Meanwhile, certain guards that changed teams saw significant changes in their opponent PISS. For example, Mo Williams went from a PISS of 19.2% in Portland in 2014 to 14.8% last season with Charlotte and Minnesota. Steve Blake saw a drop from 27.8% in Portland in 2014 to 16.9% last season with the Warriors and Lakers.
We’ve seen that teams can design and implement schemes that influence PISS, but does PISS truly matter? Should teams try to induce PISS?
The chart below plots opponent PISS to DRtg for each team in each of the last 2 seasons. The two statistics are correlated. Higher opponent PISS tends to predict a lower DRtg. Among the top 15 team seasons in Opponent PISS, 13 were in the top 18 in DRtg.
Our analysis leads to several conclusions.
- NBA defenses can have a significant impact on opponent shot selection.
- The impact on opponent PISS seems to be less a product of individual perimeter defensive skills and more a result of team scheme and interior defense.
- Inducing opponent PISS correlates with defensive efficiency.
- Portland is really good at inducing PISS. They have a good defensive system.
Offensive spacing
With the right personnel, an NBA team can space five players around the halfcourt such that all five players are simultaneously a threat to score efficiently. (This is in part due to the somewhat arbitrary 3-point line that offsets the decrease in FG% that a player typically experiences as he moves away from the hoop.)
When an offense is successful in this spacing, the defense must guard 5 distinct locations at once, making doubling or helping difficult if not impossible.
The most efficient shot on the court is still at the hoop. An offense can have one player roam near the paint, but two players in that area (with their defenders) is a crowd. The other four players need to be further from the hoop.
The mid-range jumper is not nearly as efficient as a 3-pointer for a capable perimeter shooter. Thus, the best spacing occurs when the other four offensive players are behind the arc.
The most efficient 3 is the corner 3, and there are 2 corners. An offense is wise to try and station players there. (We don’t mean that they are standing still in the offense. Rather, the offense is designed to consistently consider moving players into those areas.) That leaves 2 offensive players that have to play above the break.
The above-the-break 3 is a more difficult shot than the corner 3. So, these two above-the-break players must be legitimate perimeter shooters. Portland has 2 great ones in Lillard and McCollum.
In addition, it is usually the players above the break that are used to attack the lane (perhaps off a screen) and to draw help defenders leaving teammates open on the perimeter (and specifically, in the corners) for 3s. Portland has an elite penetrator in Lillard.
So, how did Portland acquire these two players, Lillard and McCollum, which are so important to the success of their offense?
The draft
Portland drafted Lillard 6th overall in 2012, and they drafted McCollum 10th overall in 2013. It’s important to note that Portland did not have to go to the very top of the draft to acquire this talent. Instead, they took advantage of 3 draft market inefficiencies.
First, they drafted guards. Even though the modern NBA is so focused on perimeter play, NBA teams still use the top of the draft to reach for bigs. As a result, top tier guards are available in the mid and late lottery.
3-point shooting is essential for optimal spacing in the modern NBA. Yet, many teams still do not prioritize shooting in draft picks. Even teams heavily focused on analytics don’t put enough of an emphasis on perimeter shooting for prospects. My theory on this is that these organizations are putting too much emphasis on draft models based on regressions. Remember that regressions use what worked in the past to predict what will work in the future. 3-point shooting was not as important in the past, and so regression will not predict it will be important in the future.
Lillard made 246 of 630 (39%) 3-point attempts in college. McCollum made 217 of 576 (38%). Portland was able to steal these talents later in the lottery because teams at the top aren’t prioritizing perimeter shooting.
Finally, Portland exploited the underrating of small-school prospects (and I’m using “small” to mean not a typical spot to find NBA prospects). McCollum played for Lehigh. Lillard played for Weber State. First, let’s acknowledge that college scouts do not always make the right choices. This is especially true for guards where the margins between getting a call from a major program are small. Let’s also acknowledge that players can develop while in college. The best 18-year-olds are not necessarily the best 20-year-olds.
Some are concerned that prospects from smaller programs don’t face tough enough competition in college. Quality of competition is an individual experience. You better believe that Lillard was swarmed by every defense he played. He was by far the best player on his team. In contrast, a Kentucky guard that has Towns and Cauley-Stein to dish to might have a lot more space.
Portland found talent in the draft because they were willing to use mid to late lottery picks on guards from small schools that could shoot.
If it feels like you’ve heard this story before, it’s because you have. (Steph Curry-7th overall from Davidson and Klay Thompson-11th overall from Washington state.)
This season, Lillard and McCollum are 3rd and 10th in above-the-break 3-point attempts. (Curry and Thompson are 1st and 6th.) On those attempts, Lillard is shooting 37.7% and McCollum is shooting 39.2%. This means that one of their above-the-break 3-point attempts generates at least 1.13 points on average. Overall on offense, Golden scores 1.12.5 points per possession (and they lead the NBA.) Opponents have to respect the 3-point shots of Lillard and McCollum above the break. This is a major piece of a well-spaced offense.
The corner 3
Last NBA season, the corner 3 accounted for only about 7% of the typical NBA offense. That number varied from a high of 12.4% for the Houston Rockets to a low of 3.8% for the Minnesota Timberwolves.
In spite of being such a small percentage of the overall offense, effective use of the corner 3 can be highly predictive of overall offensive efficiency. More specifically, teams that use the corner 3 more often tend to be more successful. We’ll denote the ratio of a team’s made corner 3s to total FGA as C3PM/FGA and use this ratio as our proxy for effective corner 3 usage. The following chart plots this ratio to a team’s ORtg.
Perhaps, the most striking characteristic of the chart is the extent to which Houston is an outlier. Over time, the NBA has trended towards a higher usage of corner 3s. See the chart below that tracks the use of the corner 3 (as a percentage of the total offense) from 1996-97 through last season. Houston might simply be the most progressive of the NBA organizations in terms of this movement and a representation of what a typical NBA offense might resemble in 5 to 10 years.
There are at least two reasons for the corner 3 trend and its relationship to overall offensive efficiency. First, it’s a good shot. It’s good in the sense that it tends to be very efficient. The chart below shows that shots from the corners are nearly as efficient as shots at the hoop and far more efficient than shots from mid-range. In the last five seasons, the corner 3 has produced 116 points for every 100 corner 3 attempts. For comparison, the best offenses in the NBA last season produced just under 110 points per 100 possessions.
The value of the corner 3 extends beyond its efficiency as a shot. When used appropriately, it can create added space near the hoop, making it is easier for the offense to drive, cut or post up. Thanks to SportVU’s spatial tracking system, we can now measure how often offenses station capable shooters in the corner.
We first filtered all plays to identify halfcourt sets where the defense was set. (We removed transition plays.) When then froze the play at the moment the shooter started his shot. At that moment, we recorded whether or not the offensive team had capable shooters in each corner.
We considered a 3-point shooter to be “capable” if he shot more than 0.05 3-pointers per minute played and made at least a third of his attempts. We used all 3-point attempts, and not just corner attempts, because it generated a much larger sample set to make our classifications.
Which teams more regularly had capable options in the corners? Which teams rarely had capable options in the corners? The following chart plots each team’s average number of capable shooters in the corners at the time of the shot to ORtg.
The top 4 teams in terms of capable shooters in the corners were the Rockets, Cavs, Hawks, and Clippers. Each team in the top 4 had an ORtg of at least 104.2, and the group averaged an ORtg of 107.0. The bottom 4 teams were the 76ers, Timberwolves, Knicks, and Hornets. All four were in the bottom five in ORtg last season. Each team had an ORtg below 100, and the group averaged an ORtg of 96.9.
Portland ranked 17th in 2014-15 in capable corner 3 options. That number is misleading. Nicolas Batum fell short of qualifying as “capable” because he only shot 32.4% in 2014-15. His career 3P% of 36.1% suggests he would get the respect in the corner to create the proper spacing for his teammates in the halfcourt.
In 2015-16, Portland is using the corner 3 to turn an otherwise below-average offensive player into a significant offensive contributor.
Aminu
In the modern NBA, the ball-screen has become standard practice. It is much easier for defenses to switch on screens than to fight through them, provided the defense has the type of players that can guard multiple positions.
Al-Farouq Aminu is one of the best positionally-versatile defenders in the game. Aminu stands about 6’9” with a wingspan that’s 7’3”. He’s incredibly long, agile and athletic.
Aminu gives Portland flexibility on defense, but he’s never been a great offensive weapon. Before this season, his career high in FGA per game was 6.2, and that was while playing over 27 minutes a game.
This season, Aminu is averaging 10 points per game and he’s doing so with an eFG% that’s better than Isaiah Thomas, DeMarcus Cousins, John Wall, and Carmelo Anthony. That’s not to say he’s a better offensive player than these others. Instead, it says that Portland has found a way to optimize his offensive contributions.
Check out his shot chart courtesy of NBA.com. Almost 20% of his shots, and nearly half of his threes have come from the corners, where he’s shooting 39%.
If Aminu were asked to do what Lillard does on offense, Aminu would be incredibly inefficient. But since Portland has Lillard to lead the offense, Aminu can fit perfectly into a role where he helps space the floor and shoots incredibly efficiently when called upon.
Lineup construction
We recently blogged on the difficulty of constructing a proper lineup. Lineups have to be good both offensive and defensively. They have to be successful on the interior and on the perimeter. Most players do not have the ability to do all of the above. The best lineup constructions piece together complementary skill sets in a way where everyone’s game is optimized.
For Portland, Aminu’s defensive abilities free up others on the team for less difficult defensive assignments. Offensively, Lillard’s skill allows Aminu to play in the corners and off the ball, which optimizes Aminu’s offensive skill-set.
Final thoughts
It is difficult to compete in the NBA. After losing four starters from a year ago, most would have expected Portland to struggle this season and probably for a few more. Instead, Portland has shown how well they understand how to win in the NBA. They employ good systems that optimize player skills. They properly assess talent in the draft and free agency. They assemble proper lineups.
This past offseason, Portland didn’t begin a multi-year rebuild. They reconstructed, and they’re competitive again. In their last 18 games, Portland is 15-3 with a net rating of 8.2.