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A New Method for Evaluating Players, Part II: Explanation of TPS
September 30th, 2009 by Jon Nichols

As I alluded to in my last post, something I’ve wanted to do for a long time was to make a player rating system that is totally customizable.  Every team has different needs at different times, so the one-number-fits-all style of player rating systems, which has been the norm, seems inappropriate in certain situations.  Today I would like to explain to you something I’ve created called the TPS (Talent Plus Style) player rating system (movie reference: when I produce TPS reports in the future, just know that I did see the memo and I won’t forget to include the new cover sheet).

Why TPS?  As I said in my last article:

Let’s say Shaquille O’Neal rates better than Rashard Lewis in Player Rating System X.  The Magic should try to swap Lewis for Shaq, then, right?  Obviously not.  Orlando needs a big man (calling Lewis “big” is a stretch, but go along with it for now) that can stretch the floor and give space for Dwight Howard down low.  Suddenly, we’re doing so much contextual research for Player Rating System X that the player rating itself isn’t that useful anymore.  Instead, we’re relying on shooting percentages, shooting tendencies, rebounding ability, defensive ability, etc.

Having the flexibility to specify what you are looking for in particular from a player makes things easier for talent evaluators and more fun for fans.  There are a couple of things about TPS that make it very useful:

  • Every variation of TPS ratings is adjusted for position.  A center who can shoot three-pointers at the league average is much more valuable than a shooting guard with the same efficiency.  Likewise, a point guard with a league average rebounding rate is probably pretty good in that respect.  Not only does adjusting for position level the playing field, but it also makes it easier to find players who are unconventionally good at things.
  • TPS can include my original Composite Score rating system if desired.  As you may or may not recall, Composite Score is a combination of the Offensive/Defensive Ratings developed by Dean Oliver, PER /counterpart PER, and offensive/defensive plus-minus.  Additionally, if you only like some of those components, you can pick and choose which ones to include.  Composite Score often serves as a base for many of the ratings I develop when I’m playing around with TPS.  It provides a nice “all-around” measure for players so that even when you want to focus on specific skills, you don’t ignore everything else that occurs on a basketball court.
  • There are literally an infinite number of possibilities for how you can rate players.  Up to 25 different variables can be included, and each can be assigned a different weight, depending on what’s important.
  • Every variable is adjusted either per-minute or per-shot-attempt.  Players who perform admirably despite limited playing time will still rate well.

Which variables can be included in TPS player ratings?  They can be broken down into three categories:

Composite Score Stats:

  • Composite Score
  • Offensive Composite Score
  • Defensive Composite Score
  • Offensive Rating
  • PER
  • Offensive Plus-Minus
  • Defensive Rating
  • Counterpart PER
  • Defensive Plus-Minus

Shooting Stats:

  • Close Attempt Percentage (=close attempts/total shot attempts)
  • Close True Shot Percentage
  • Midrange and Post Attempt Percentage (=midrange and post attempts/total shot attempts)
  • Midrange and Post True Shot Percentage
  • Three-Point Attempt Percentage (=three-point attempts/total shot attempts)
  • Three-Point True Shot Percentage
  • Fouled Attempt Percentage (=fouled shot attempts/total shot attempts)
  • Fouled True Shot Percentage
  • Assisted Rate (=assisted field goals/total made field goals)

Other Advanced Stats:

  • True Shot Percentage
  • Free Throws/Field Goal Attempts
  • Pure Point Rating
  • Assist Rate
  • Turnover Rate
  • Rebound Rate
  • Usage Rate

As you can see, I did not develop all of these statistics (for some I just adjusted them for position and use them as components in my ratings).  Offensive and Defensive Ratings were developed by Dean Oliver and can be found at Basketball-Reference.com.  PER and many of the other advanced stats were developed by John Hollinger.  I used Basketball-Reference and Knickerblogger.net to gather these.  For player names and teams, I used Dougstats.com.  For positions, plus-minus, and Counterpart PER, I used 82games.com.  Additionally, although I calculated the shooting stats myself, similar numbers can be found at 82games.  To calculate the shooting stats, I used the play-by-play data available at BasketballValue.com.

The ratings I have come up with so far are all based on a 0-100 scale, with 50 being average.  Remember that these ratings are adjusted for position, so a player with a 50 is average for his position.

To give an example of what TPS can do, I have created a rating called Playmaker Score.  This number rates players on all of their abilities, but especially their ability to create shots for others.  It considers a player’s Composite Score, Assisted Rate, Pure Point Rating, and Assist Rate (remember that Assisted Rate measures how many of a player’s shots were assisted by others while Assist Rate estimates how many of teammates’ field goals an individual player assists on).  To see the numbers, go to:

Link

This is just one rating that I threw together pretty quickly.  Still, it gives some interesting results and shows what TPS is capable of doing.  Over the next few weeks, I will come out with some similar player ratings using TPS.  If you have any questions or suggestions, feel free to comment below.

P.S. If you’re wondering what movie I referenced earlier, check out: Link to video


One Response  
Crow writes:
October 2nd, 2009 at 12:52 am

Jon,

You are going in a good direction. I look forward to seeing your various TPS rating flavors and to the day when the tool is fully available to others.

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