Tom's Toolbox: An NBA stats glossary

USA Today Sports

Tom's Toolbox: An NBA stats glossary

Today’s NBA looks alien compared to a decade ago. The conversation and the lens by which we view the NBA has changed with it.
You may have heard some new terminology in this space and go, huh? I don’t want to lose my readers, so with that in mind, I decided to write up a glossary that you can use as a trusty guide next time I bring up an acronym that sounds like a bill proposed on Capitol Hill.
Let’s call it Tom’s Toolbox. Here are some of my favorites:
Offensive Rating
Points scored by a team every 100 possessions, also commonly referred to as offensive efficiency. 
Offensive rating adjusts points per game to give a better sense of a team’s ability to put the ball in the basket. To calculate, you simply take the points that a team scores and divide it by the number of possessions it used and then multiply that figure by 100. Ta-da!
Uh, why 100?
It is roughly the number of possessions in an NBA game. Offensive rating (ORtg for short) also helps to compare teams in the past and is really useful when comparing lineups that don’t play the same minutes. 

Where to find it: and Note: possession data can differ from site to site. Some sites estimate the number of possessions in a game because it’s not historically tracked in the box score. You have to do some back of the napkin math to calculate possessions and so it can vary slightly. I use for looking at today’s teams and those dating back to 1996-97, the first season available on the league’s site. If you want to go back further and size up teams with Kareem Abdul-Jabbar on it, I recommend using
Defensive Rating
This is the counterpart to Offensive rating, which adjusts for pace. Defensive rating, also known as defensive efficiency, is simply the number of points allowed per 100 possessions.
Net Rating
You’ve probably seen this a lot in modern NBA writing when talking about lineups or how good the Milwaukee Bucks are. It’s simply offensive rating subtracted by defensive rating. Boom: net rating. Another way to think about net rating is that it is point margin once you control for pace.

Offensive rating, defensive rating and net rating can be super noisy in small sample sizes. As a rule of thumb, I like to look at lineups with at least 100 minutes played before I give it serious weight. Even then, it gets wonky.

There have been studies that show net rating is a better predictor for team success than using win-loss record. That’s because net rating strips out the flimsy randomness that can decide close games. 

PER (Player Efficiency Rating)
The most popular all-in-one player metric in basketball. PER set out to measure productivity on a per-minute basis. League average PER was set at 15, which may be its best quality. You can get a pretty good handle of how good a player is by glancing at his PER. Twenty is great. Ten … not so much.

PER has its issues. For example, it likes chuckers more than it should. And it doesn’t do a good job of capturing defense because box scores don’t really measure defense very well. And it uses box score data to inform it. Blocks and steals only go so far. 

I still look at PER as a rough thumbnail portrait of a player and probably more than I should. It’s a handy tool that can sometimes get you in trouble if you use it too much and it can’t do as much as you’d like.

Usage rate
This “rate” is the estimated percentage of team possessions that a player uses via field goal attempt, free throw attempt or turnover while on the floor. Translation: How much offense is this player responsible for through his scoring? 

It doesn’t perfectly answer that question but it’s a helpful way to see how much a player is chucking or not. High usage players in the 30s (or 30 percent, to be specific) are typically your MVP candidates who put up huge point totals. 

I like to look at usage rate to see if a player is more of a role player. Usage rate could also be called role rate and it’d get at the same thing. Turnovers are included because a player “used” up the possession with a miscue. However, assists are not included in usage rate. 

This stat can be more informative than using plain old field goal attempts to show how much offense is run through a player. 

Find it on

Win Probability Added
The beginning stages of the holy grail. Which player raised (or lowered) his team’s chance of winning through his shot attempts and turnovers? This is definitely not a comprehensive metric. It doesn’t see a host of important things like passes, screens and rebounds that help teams win.

This stat is more descriptive than predictive. I like this one for MVP races because that is more about what you did as opposed to what you will do. 

Offensive Rebound Rate
What percentage of available offensive rebounds does this player or team collect while he’s on the floor? That’s what Offensive Rebound Rate is after. 
It’s hard to get an offensive rebound if your team makes all of their shots. Like, really hard. So hard it can’t happen. Therefore, a team can have a “good” offensive rebounding night even if it’s raw total of offensive rebounds is low. The best teams collect 30 percent of their misses. So if you only have three offensive rebounds in a game (bad), but your team only missed 10 shots (wow!), that’s doing pretty good.
On the flipside, it’s much easier for a poor-shooting team to rack up a bunch of offensive boards simply because there are so many of them to be collected. For coaches, it’s more helpful to look at this number rather than raw offensive rebounds to determine how their team crashed the boards. Oh, and good news for bench players: this stat is playing-time agnostic so you can show you’re a great offensive rebounder without having to log 30 minutes a night.
Offensive rebound rate is also one of the main pillars of advanced stats in basketball, which Dean Oliver called the four factors. If you’re good at collecting your available offensive rebounds, you’ll be pretty successful.
Defensive Rebound Rate
This is the other side of the coin. Defensive rebound rate is why the Golden State Warriors' starting five has been so underwhelming this season.
Win Shares (WS)
Another all-in-one metric that attempts to quantify a player’s contributions to winning. Find it on It’s a counting stat that tries to answer the question: How many team wins is this player responsible for?
Like every all-in-one metric, this one has to be handled with care. If Player A has more win shares than another Player B, that doesn’t necessarily mean he’s better. He could have just played more. The PER equivalent is win shares per 48 minutes or more commonly seen as WS/48. League average WS/48 is .100 which is a little harder to remember than PER’s 15.
Win shares has its blind spots, too. It doesn’t use lineup data, which can help find players that do things that the box score doesn’t pick up. It’s shown to be a tad biased towards players with good team defenses because its defensive component relies more on the team’s output rather than individual box score stats like blocks, steals and defensive rebounds. 

Find it at
RPM (Real Plus-Minus)
The most ambitious of all the popular all-in-one metrics, this statistic attempts to quantify a player’s impact on team performance, scaled on a per 100 possessions basis. This leans heavily on on-court lineup data and controls for teammates and opponents. It’s a blackbox stat which means the formula is not publicly available and can’t be reproduced. That lends itself to some skepticism in academia.
RPM is a rate stat like PER and can be translated into a counting stat. RPM Wins is the counting stat equivalent of win shares. It’s a fun stat but it can be noisy in small sample sizes. If you want a full, way-smarter-than-me breakdown of RPM, read this.
True-Shooting Percentage (TS%)
One of my favorite stats. How efficient is a player with his shot attempts once you consider free throws and 3-pointers? It’s scaled roughly to your standard field goal percentage, so a .600 is great while .400 is … not great, Bob.
True-shooting percentage derives its name from the concept of true shots. “True” shots are field goal attempts plus fouled shots. Once you account for those free throws, you get a fuller picture of the player’s scoring night and how efficient he was getting to that point total.
Another cool thing: true-shooting percentage is points per true shot, divided by two. The divide by two is to keep it on the same scale as field goal percentage.
Effective field goal Percentage (eFG%)
Also seen as adjusted field goal percentage. The calculation is simply field goals plus 1.5 times 3-point field goals divided by field goal attempts. If you don’t make any threes, your effective field goal percentage will be exactly your field goal percentage.

Whereas true-shooting percentage includes free throws, this stat is just field goal percentage with proper weighting for three-pointers. This stat naturally rewards 3-point shooters who don’t need a lot of shots to score a lot of points.

Follow me on Twitter (@TomHaberstroh) and bookmark for my latest stories, videos and podcasts.

NBA’s biggest questions before return

NBC Sports

NBA’s biggest questions before return

The NBA is back. Well, sort of.

No Stephen Curry, Draymond Green or Klay Thompson.

No Trae Young, Karl-Anthony Towns or D’Angelo Russell. Teams in large markets like the Chicago Bulls and New York Knicks will be watching from home. Charlotte, Detroit and Cleveland: back to the big board.

But for everyone else, NBA games are upon us. 

For weeks, the league office, the board of governors and the National Basketball Players Association have gone back-and-forth on a variety of ideas with the explicit goal of resuming the NBA season in some form. Everyone wanted to play basketball. That was never in doubt. But not everyone wanted to play basketball if it meant a substantial risk of getting infected with coronavirus or suffering a major injury due to the extreme circumstances.

Following Thursday’s board of governors vote, the NBA believes it has a plan to account for both of those risks. But as they say, the devil is in the details. 

As much as we’d like to believe we have all the answers and everything is wrapped with a bow, the world does not work that way. There’s still plenty of uncertainty in this plan.

Here are seven lingering questions as the NBA proceeds towards July 31.

Is it, you know, safe?

“It’s about the data, not the date.” Commissioner Adam Silver said those words on a conference call with the media in late April while addressing the NBA’s eventual return-to-play plans.

Well, it’s early June and we have a date. The data? That’s another story.

The league and the players union have insisted that health comes first and there are signs that they’re taking that side of the plan very seriously. For one, they’ve planned to convene at one central site. Secondly, according to an ESPN report, there are plans for daily testing, which would be an enormous undertaking financially, logistically and politically. 

In my discussions with epidemiologists and infectious-disease experts, those were critical elements of a safe return-to-play plan, but there are still finer details that need to be addressed. Who’s allowed in the bubble? What kind of tests will those people receive? Does the league have the requisite supplies? What about hotel, food and maintenance staff testing? 

Above all, the NBA would be wise to have a concrete plan in the case that one or multiple people inside the bubble test positive. How many positive tests are acceptable? One? One per team? Does a positive test in August have different implications than one in October presumably in the Finals? 

In talks with teams around the league, this is one of the thornier issues that team executives need the league to address. A strictly-enforced guideline on how to handle positive tests would do a lot to strip away the emotions that can get in the way of making sound decisions and help the league protect its employees -- players, coaches, execs or team staffers -- from harm.

Not every team is in the same position. Take the New Orleans Pelicans, whose head coach, Alvin Gentry, is 65 years old. His top assistant, Jeff Bzdelik, is 67 years old. The CDC states that people 65 years or older are considered a high risk for severe illness from COVID-19. If a positive test pops up on their team, does the NBA need to take stronger action than other teams? What if they played a team with a positive test? 

Should Gentry and Bzdelik have to wear a mask on the sidelines? Should they be on the sidelines? These are thorny questions that don’t appear to have answers at the moment. 

And that’s just one coaching staff. What about referees? The NBA’s longest-tenured referee, Ken Mauer, is 65 years old. So is longtime NBA referee Michael Smith. If Gentry and Bzdelik have to wear masks, do Mauer and Smith have to wear masks as well? Can you officiate that way? And would the NBA let them officiate games of teams if they officiated a team with a recent positive test?

It feels a bit like we’re putting the cart before the horse. We’ve already planned a return date when one of its teams, the Spurs, haven’t deemed it safe to reopen their own practice facility because of coronavirus concerns

All these questions are tricky because there is still so much we don’t know about the novel coronavirus. But teams are hoping the league addresses them clearly in a league-issued document.

Will NBA players take a knee?

As the league plots a return to the court, NBA players, the vast majority of whom identify as black or African-American, are facing more than a deadly pandemic. Perhaps no one put it more clearly than former NBA All-Star Caron Butler, who said Wednesday night on the NBA’s official platform: “We’ve been dealing with two viruses: COVID-19 and racism.”

When it comes to social issues and civil rights, NBA stars have been some of the most outspoken in all of American sports. These days have been no different. LeBron James, who in 2017 called the President a “bum” for his response to Stephen Curry’s White House rebuff, recently blasted Drew Brees on Twitter after the Saints quarterback reiterated that kneeling during the anthem is disrespectful to the military.  

Players like Curry, Kyrie Irving, Jaylen Brown and Towns have marched or attended rallies in recent days to protest systemic racism and police brutality in the wake of George Floyd’s murder at the hands of law enforcement. One of the most vocal activists in the country has been Floyd’s friend, Stephen Jackson, a 14-year NBA veteran.

While the NHL has plans for a return and MLB is negotiating for one, there’s no doubt that the NBA will be the main draw in town. As such, the NBA megaphone may be louder than ever. 

However, some players already feel a restart may be taking away from the larger societal conversation.

Los Angeles Clippers point guard Patrick Beverley is known as one of the fiercest competitors in the league, but he strongly disagreed with the renewed focus on basketball.

Beverley wasn’t alone. When news broke Wednesday of the imminent agreement on return-to-play, Brooklyn Nets forward Wilson Chandler tweeted: “Government can’t wait until the NBA start the season back. Need a distraction from the bulls*** that’s going on. Always in need of a distraction.” Miami Heat guard Andre Iguodala, Los Angeles Lakers forward Kyle Kuzma, San Antonio Spurs forward Trey Lyles each retweeted Chandler’s sentiment with supportive comments.

On Wednesday night, Kuzma went further, tweeting a photo of Brees kneeling with teammates with the caption: “This shows you that there are a lot of people & companies out there right now that will say they stand with us but only do it so they dont get bashed not because they mean it.”

League insiders have been supportive of NBA players protesting in the streets of America. But what happens if they take those protests to the basketball court? Or the national anthem itself? 

If NBA players decide to kneel during the anthem like Colin Kaepernick and other NFL players did, it will be in violation of NBA rules. In the Player/Team Conduct and Dress section of the Official NBA Rule Book, Rule 2 states: “Players, coaches and trainers are to stand and lineup in a dignified posture along the sidelines or on the foul line during the playing of the National Anthem.”

In 2017, the commissioner said he expects players to stand and follow the rules. The players did fall in line, choosing instead to stand with interlocked arms during the anthem for several games. 

NBA players might choose a different demonstration this time around. Kneeling during the anthem is officially against NBA rules, but it remains to be seen what the official punishment would be if NBA players decided to protest in that manner. One thing’s for sure: The world will be watching.

Is the scheduling fair?

The NBA landed on a compromise. They could have played the rest of the regular season or gone straight to the playoffs. Playing the rest of the regular season would mean teams would have to play 17 games on average. The NBA decided to split the difference and play eight.

Fair enough. But who would those 22 teams play in those eight games? One idea is to pick up where they left off before the league shutdown on March 11 and play the next eight games on the schedule. Seems fair, right?

That doesn’t work in a league where eight teams are no longer playing. For example, the Spurs’ next eight opponents were, in order: Denver, Minnesota, Memphis, New Orleans, Chicago, Utah, Utah again and finally a repeat date with Minnesota. Minnesota and Chicago aren’t going to be in Orlando. 

So what do you do? If you take those three games out and move up the next three opponents in line, the Spurs would then play Denver, Golden State and Sacramento. Uh, oh. Golden State won’t be there either. If you take Golden State out and look to their next scheduled game … you find Golden State, again. The next opponent would be New Orleans. To just get to eight games, the Spurs would have to look at their next 15 games.

But that sprouts two more problems. First, the Spurs just replaced non-playoff teams opponents with playoff-aspiring teams. Is that fair? By pure luck, the Grizzlies have already played 15 of their 16 scheduled games against the eight non-bubble teams, going 11-4 against the league’s doormat clubs. On the other hand, the Spurs just got five of their easier games erased and replaced them with harder opponents. Yikes.

And that brings the second issue. The Spurs’ eighth game against New Orleans? The Pelicans would be long done by then. 

To solve this issue, the league could just scrap the regular-season schedule and play a new set of games with fairer distribution of games.

You might say, “Who cares? Just play the games.” Try telling that to New Orleans, Portland, San Antonio and Sacramento, four small-market teams that are all but dead-locked in the standings and fighting for that final playoff spot. Every detail matters. 

Of course, there’s nothing fair about a pandemic. But there are things that the NBA can control. This is one of them, and it could have long-lasting ripple effects, especially for small market teams.

Given the huge moats surrounding the No. 8 seeds (Magic have a 5.5-game lead on the Wizards and Grizzlies have a 3.5-game lead on three teams), schedule equity could be a moot point anyway. The play-in game (it’s not a tournament) only comes into play if the ninth seed is within four games or fewer of the eighth seed at the end of the eight games. Even then, the No. 9 seed would have to win twice against the No. 8 seed to punch their ticket. Not to throw a wet blanket on the bubble teams, but if you’re not in the eighth seed by now, you’re basically Lloyd Christmas talking to Mary Swanson.

Will players be physically ready?

This is not like the 2011 lockout. This is a pandemic, not a work stoppage. In previous lockouts, the players regularly played pick-up games, sometimes for charity in front of crowds, to stay in shape. This time around, NBA players haven’t been allowed to play five-on-five in months. 

Early on in the process, the NBA presented a plan in which all 30 teams would return under the bubble environment, but that idea was met with considerable resistance, according to league sources. Multiple players and teams expressed disagreement with that idea and would rather not play than risk injury and infection. Portland was the lone team that dissented during Thursday’s vote and its star player, Damian Lillard, went on the record in late May to say he would sit out unless the Blazers could fight for the playoffs. Lillard told Yahoo Sports he was just coming off a groin injury and that factored into his calculus: “I'll be putting myself at risk for injury and reinjure myself.” 

The Blazers were given that chance to make the playoffs and still the team voted against. While it’s unclear how much of a role Lillard’s comments played into the Blazers’ position, it’s telling that even a superstar with five years guaranteed after this season is still iffy about risking it. According to reports, the Blazers preferred other formats and listened to their players before making the call.

Imagine being a free agent on a bubble team this summer and getting your body ready to play potentially only eight games. Is it worth it? If Washington Wizards sharpshooting forward and unrestricted-free-agent-to-be Davis Bertans felt the risk wasn’t worth the reward, I wouldn’t blame him for sitting out these games to protect what might be the biggest payday of his career.

Athletic trainers, strength and conditioning coaches and medical staffs will be hard-pressed to get their players ready in time for the July 31 kickoff. Three months of no basketball will disrupt the kinetic chain of joints, muscles and ligaments that make NBA players so thrilling to watch. 

On that note, prepare for some bad basketball as players work themselves back into shape. According to Basketball Reference tracking, the two biggest drops in year-to-year offensive efficiency in NBA history came during lockout seasons in 2011-12 (minus-2.7) and 1998-99 (minus-2.8). With a denser schedule and accelerated training camps, teams coughed up the ball at higher rates and shooting percentages bottomed out. Expect more of the same in the coming months. Basketball is back … ish.

What about the other eight teams?

The NBA’s 22-team return-to-play plan means we won’t see the Golden State Warriors in action until December. Here’s a crazy thought: Stephen Curry, Klay Thompson and Draymond Green will go 18 months without playing in real games together. Life comes at you fast in the NBA. 

I hope the other eight teams will be able to participate in some sort of charity tournament or other competition between now and whenever the 2020-21 season starts (Curry vs. Thompson showdown, anyone!?). Nine months without playing basketball is a long time -- especially for teams like the Minnesota Timberwolves who remade their roster at the trade deadline and had almost no time to build on-court chemistry. D’Angelo Russell and Karl-Anthony Towns played in one game together in the 2019-20 season.

There’s also the issue of the draft and the draft lottery. For the teams that make the playoffs, draft order will be based on their regular-season record, including their eight “seeded” games. But for the lottery teams, the lottery odds are locked in as of their record on March 11. 

That eliminates the incentive for the Wizards to tank the eight-game slate in epic fashion, go 0-and-8 and leap the Charlotte Hornets and Chicago Bulls in the draft order odds. As my astute colleague Dan Feldman points out, that would raise the Wizards’ odds of a top-three pick from six percent to 15 percent. 

My hope is that the Wizards wouldn’t do that for the spirit of the competition, but the fact that the NBA pre-empted such an egregious tank job by freezing draft odds on March 11 is a tacit admission that teams are incentivized to throw games. We should just abolish the draft all together and let prospects choose their destination like we do for NBA free agents already. But that’s a discussion for another day.

Charlotte and Chicago have to be happy the league stepped in. If there’s a silver lining for the Delete Eight, as John Hollinger brilliantly dubbed them, it’s that they can finally move forward with clarity. The draft is tentatively set for Oct. 15 and the Bulls, who have picked seventh in the last two drafts, have the seventh-best odds in the draft lottery. At least there’s some semblance of normalcy in all this.

How weird is this going to be?

Super weird, at first. Are we going to have ads covering up the seats? Are we going to pipe in crowd noise? How much will that taint the viewer experience? 

We’ll probably get used to that, just like we’re used to laugh tracks on sitcoms. We better get used to it. Believe me, the NBA or the players’ union won’t allow raw audio from the court to be heard at home. That screams PR disaster. 

Even if they could offer an “uncensored” feed for a nominal fee to scrape together some extra dough, I’m guessing the unsavory stuff would trickle out onto the internet in no time. There are better ways for the NBA to have fans feel more engaged and closer to the action. Referee cams? Alternate broadcaster teams? NBA Jam-like flames when a player hits consecutive shots? Let’s get weird.

What does this mean for the NBA beyond 2020?

Even before this pandemic hit, I’ve argued that the NBA should kick off the regular season on Christmas Day. It’s time to make it a permanent change. Most fans don’t tune into the NBA until Christmas anyway (the league office programs its national TV schedule accordingly). The NBA has owned that day on the sports calendar. Just make it official already.

Although the NBA says that it will “likely” begin the 2020-21 season on Dec. 1, I wouldn’t be surprised if they buy some more time to raise the chances that they can get at least some fans in the seats. The commissioner has told players recently that ticket revenue typically makes up 40 percent of the league’s income, according to a report from Shams Charania. That’s an enormous pile of cash to leave behind in 2020-21. 

It’d be difficult to slowly re-integrate fans into the stands without shutting down for a period of time, allowing arena staff to reset protocols and observe new health guidelines. Perhaps the NBA can gradually fill seats on the fly without a pause in the schedule, but finding a sensible and healthy way to recoup ticket revenues should be a top priority for 2020-21.

From a fatigue standpoint, a Dec. 1 start for next season seems to be pushing it. The Finals will end sometime in early October and training camp would be slated for Nov. 10. Do we really want the league’s best players and teams to be coming into training camp ragged for 2020-21? After an injury-marred season from Curry and Williamson, I’d imagine the league will be looking to ensure every possibility that its top draws are as healthy as possible.

It seems the dates for 2020-21 are moving targets, according to reports from ESPN. My educated guess is that the league settles on Christmas Day as the 2020-21 season opener, pending any major coronavirus developments. A lot can change between now and then.

Follow Tom Haberstroh on Twitter (@TomHaberstroh), and bookmark for my latest stories and videos and subscribe to the Habershow podcast.

NBA has more work to do after George Floyd response

NBA has more work to do after George Floyd response

Out of 30 NBA teams, 28 issued official statements on Twitter regarding the George Floyd killing. The only two teams that failed to issue a statement with the New York Knicks and San Antonio Spurs, as of the morning of June 3. 

Spurs coach and team president Gregg Popovich condemned police brutality, white privlege and leadership issues in an interview with The Nation. The Spurs organization have not yet publicly backed Popovich's comments.

Out of those 28 teams, 26 cited Floyd by name, but only six official statements released on Twitter included the words police, law enforcement, or those in uniform. The Washington Wizards released possibly the strongest statement, notably doing so on behalf of their players, including the phrase, "We will no longer tolerate the assassination of people of color in this country."