Introduction

The shortage of meaningful defensive data in the boxscore is a re-occuring topic among fans and analysts. Basketball statkeepers chart blocks, steals and defensive rebounds (plus fouls) for a player whose team is in a defensive possession, but there is plenty of uncharted action which preceeds a possession-altering action.

The advanced stats movement has brought us interesting concepts such as adjusted plus/minus, an attempt to specify an originally player-unspecific stat (offensive and defensive team efficiency) by adjusting for quality of teammates and opponents while taking a large sample of data into consideration. The result is a valuable measure of overall offensive/defensive impact, but it is hardly returning a detailed performance analysis.

Several analysts have tackled the problem in the recent past. Here are key links:

• Luke Winn re-ignited the discussion in autumn 2011 with his groundbreaking work on defensive stats for several NCAA top teams.
• Rob Mahoney continued with defining categories, partly basing on Winn’s previous work.
• In measuring defense, Rod Higgins comments on the work of Winn and Mahoney while bringing in his own perspective, gained from charting the Olympiacos-Bilbao game.

For Euroleague

A Euroleague Regular Season gameday consists of 12 games, a Top16 gameday has eight. Our goal is to assemble a group of basketball geeks big and committed enough to chart every Euroleague game. One game per week per person is a doable task. If you’re interested, please contact us here in the comment sections or via contact.

At the basis of such work lies the definition of statistical categories. I find that there are four key criteria to design such categories. The categories must …

1. make a meaningful statement about defensive performance,
2. be statistically digestable,
3. be simple to understand and
4. not exceed a maximum number of categories.

• (A) Stealing / forcing turnovers
  
  1. Steals+: Steals leading to transition points, including FTs.
  2. Steals on the ball: How many times a player steals the ball vs his man.
  3. Steals off the ball: How many times a player steals the ball when helping out.
  4. Forced turnovers rate: to be defined
  5. Deflections: how many times a players knocks the ball loose and a teammate secures possession or an opponent is forced to throw it out of bounds.
• (B) Shotblocking
  
  1. Blocks+: Blocks leading to transition points, including FTs.
  2. Blocks on the ball: How many times a player blocks the ball vs his man.
  3. Blocks off the ball: How many times a player blocks the ball when helping out.
• (C) Defensive efficiency in one-on-one sequences (in PPP and FPP):
  
  1. Points allowed on post ups, measured in PPP (points per possessions); Also: Fouls conceded on post up possessions (FPP)
  2. Points (PPP) and fouls (FPP) conceded after switches (PnRs, off the ball screens, secondary breaks)
  3. Assists allowed on switches (team stat only)
• (D) Others
  
  1. Hedge rate, defined by Mahoney as “[...] Quantifying how often – or how far – a player hedges to counter a screen would provide an added level of defensive specificity.”

The point of this intiative is to A) trigger a discussion in order to B) come up with meaningful categories that would allow us to start with, ideally, Top16 2012.