So far in our 'Get To Know An Advanced Stat' series, we've looked at clear cut advanced metrics like offensive and defensive rating, true shooting percentage and effective field goal percentage, and rebound rate. This week, however, we dive into the world of advanced assist metrics, where there are still plenty of flaws and much more to be discovered.
For years, we've tracked a player's passing ability and assist making ability through raw assist totals, assists per game or at the most advanced, assists per 48 minutes to level the playing field for players who play less.
The two most popular advanced assist metrics are Assist Percentage and Assist Ratio. Assist percentage is the percentage of made teammates' field goals a player assisted on while he was on the floor. For example this season, Chris Paul is recording an assist on 54.1 percent of his teammates' made field goals while he's on the court. For comparison's sake, the next best mark is 46.8, which belongs to Stephen Curry.
Assist Ratio is the percentage of a player's individual possessions that end in an assist, where you'll find a surprising name atop the early leaderboard, as Jamaal Tinsley leads the NBA right now with an assist ratio of 44.2.
While looking at basic assist stats and these two more advanced assist measures are fine, they all still contain one basic flaw, and that's the fact that a player's ability to record an assist still hinges on whether or not the teammate he's passing to can make a shot. Now I know that a good point guard and a great passer can get teammates higher percentage looks, which therefore leads to a better chance at an assist, but still, is it fair to evaluate a player's passing ability by looking at numbers that are so obviously influenced by the quality of his teammates?
This is where the NBA's dive into SportVU Player Tracking data comes in, or at least could come in eventually, as NBA.com now carries daily updated assist measures like Passes Per Game, Free Throw Assists, Secondary Assists, Assist Opportunities and Points Created By Assists.
Chris Paul leads the league at 76.7 passes per game, and his 12.5 assists per game lead to 27.9 Clippers points a night, but it's the other three SportVU assist measures that really interest me.
A Free Throw Assist measures how many times a pass leads to a player being fouled on the subsequent (missed) field goal attempt (If it's an and-1 opportunity then the passer is simply credited with a normal assist) before knocking down at least one free throw. Russell Westbrook leads the league with 1.2 free throw assists per game, by the way. It's a new, unique and interesting enough stat, but it's nonetheless flawed, as it punishes players who may be passing to a player who isn't a great shooter from the charity stripe - think Andre Drummond, DeAndre Jordan or Dwight Howard.
The Secondary Assist is interesting in that we've heard basketball commentators and other observers reference the 'hockey assist' for some time - the pass that leads to the pass that leads to a made field goal. While you may have envisioned the leaderboard here looking a bit different than raw assists per game, it's really not, as John Wall (2.5) and Chris Paul (2.3) make up the top-two. However, and you probably know what I'm going to say here, the flaw of the stat still depending on teammates to make a shot exists here, too.
For that reason, perhaps the most valuable new stat or 'advanced' stat when it comes to passing and assists is the Assist Opportunities number. It's a pretty simple measure - the amount of times a player's pass leads to a teammate's field goal attempt. I suppose the flaw here is that the stat may reward players who play with shoot-happy chuckers that consider any inkling of space a good time to release, but it also takes into account something I brought up earlier, and that's that good point guards and passers will make passes that lead to better shooting avenues. In addition, there is potential with respect to Assist Opportunities and SportVU, as data such as the quality of shots created through these opportunities is available to teams through the camera tracking.
If you're wondering, Chris Paul, John Wall and Ty Lawson make up the top-three with 22.1, 19.5 and 18.9 assist opportunities per game, respectively.
While the first few advanced stats I explored were much more cut and dry - Offensive/defensive rating is superior to team points scored/allowed per game, True/Effective Field Goal Percentage is much more indicative of a player's real shooting efficiency than raw Field Goal Percentage, and Rebound Rate is a much better measure of a player's rebounding prowess than raw rebounds per game - advanced assist stats, as you can see, leave virtually as much to be desired as the basic assist stats they are supposed to override.
The new numbers are intriguing and the rise of player tracking data likely means there is much more to come, but for now, it remains difficult to eliminate the flaws and influence of teammates in passing metrics. One thing remains constant, however, across both basic and advanced assist metrics - Chris Paul is more than worthy of his 'Point God' moniker.