Kansas vs. Duke Defensive Scoresheet

For (hopefully) every KU game this year, I am going to be doing defensive charting of the games. For a longer intro on the defensive scoresheet project, you can read this SI article by Luke Winn (with a lot of help from David Hess). But the short version is basically that this is designed to help better credit (and debit) players for their impact on the game defensively in a way that goes further than merely citing blocks and steals and going on a player's reputation. This is a lot (seriously, a lot) more work for your resident blogger: I had to watch and re-watch a lot of possessions to figure out who to credit or debit on a lot of defensive possessions. Before I post the chart, a brief glossary, taken from here:

• Taken from the box score
  • Min – Minutes played
  • DREB – Defensive REBounds
• Tracked by me
  • FM - Forced field goal Miss – when a defender forces an offensive player to miss a shot from the field. Oliver separates FM from Blocks, but I’ve lumped them together here.
  • FTO – Forced TurnOver – when a defender forces an offensive player to turn the ball over. Again, Oliver separates out Steals, but I’ve combined them, partly because because I don’t know which plays the official scorekeeper would actually count as steals. One thing to note here is that a player who draws an offensive foul is always credited with a FTO, even if it’s just a moving screen.
  • FFTA – Forced missed Free Throw Attempt – missed foul shots resulting from a defender’s foul
  • DFGM – allowed Defensive Field Goal Made – when a defender allows an offensive player to score a field goal over him or by dribbling by him
  • DFTM – allowed Free Throw Made – made free throws resulting from a defender’s foul
• Calculated Tallies
  • Stops – the credit a defensive player gets for actions that contributed to ending an opponent possession. This isn’t as simple as adding FM + FTO + 0.4*FFTA, because the credit for a missed shot has to be shared with the defensive player who rebounds it. The formula is more complex than you might think, and includes a sliding weight for FM vs. DREB, based on how difficult those actions seem to be in each particular game, so I’ll just refer you to Appendix 3 of Basketball On Paper.
  • ScPos – Scoring Possessions allowed by a player. This is essentially just DFGM plus a FT-related factor. I’ll again refer you to Basketball On Paper for details.
  • DPoss – [Stops + ScPos] – total Defensive Possessions that were credited to (or blamed on) a player.
• Calculated Metrics
  • Stop% – [Stops/DPoss] – the fraction of an individual player’s credited defensive possessions that ended with 0 points. Essentially the inverse of offensive Floor%.
  • %DPoss – [(Min/40)*DPoss/TeamDefensivePossessions] (for a non-OT game) - the percentage of team defensive possessions faced by an individual defender. Analogous to %Poss on offense.
  • DRtg – [(1–%DPoss)*TeamDRtg + %DPoss*(100*TeamDefPtsPerScPoss*(1-Stop%))] – individual Defensive Rating. Gives a player credit for stops and scoring possessions he was directly involved in, then assumes a nebulous team-average performance in the other possessions. This is the analog of offensive rating.
  There are obvious problems with crediting players (and debiting players) for defense. If an opponent blows by KU's point guard (A) and then draws a defender (B) and dishes it to the player B was supposed to be guarding, who has an easy layup because C missed a defensive rotation, how do you divide up that pie? Ideally it would be a third for each of them, but sometimes you have to pick and choose and make judgment calls. For example, it might not be fair to ding defender B in the example above because there wasn't much he could do to prevent what happened.

Here is the table (Click the table for the full size image):

Ed. Note: I messed up some math on the table, which is why the D ratings were messed up. Thanks to David Hess for the correction. Whoops!

As far as the free throws made and missed goes, I just gave players credit or dinged them based on who committed the foul. I flirted with the idea of giving a player credit for a missed free throw when he saved a shot from going in, and dinging the other guy in a situation where Player A gets blown by and player B blocks his shot but commits a foul.

The first thing that jumps out at me is how well Perry Ellis played defensively. He had some problems at overhelping, and only half of his defensive possessions were stops, but compared to how well Jabari Parker played otherwise I'd say Ellis acquitted himself well. Elsewhere, Andrew Wiggins was the best defender on the floor, Jamari Traylor was awful, and Kansas needs to find a rim protector.