Learn a Stat: steal percentage and block percentage

Welcome back to Hack a Stat! It’s a new chapter of Learn a Stat dedicated to steal percentage and block percentage, for which advanced versions have been created.



Steals and blocks are contributions that are limited to small quantities in a single game, especially in Europe. When dealing with low numbers, it is easier to come across apparent similarities that are, actually, not similar: for example, stealing three balls in a low-paced game is different from stealing the same number in a match at high pace. Blocking 5 shots with 50 shots attempted by opponents, it is easier to make five when the opponent shots only 20 field goals. This is why we need advanced statistics that take these aspects into account.

Definition and starting data

Steal Percentage is the percentage of balls stolen compared to the opponent’s possessions played. Therefore, the number of steals is divided with the opponent’s possessions: in the case of individual stat, the number of opponent’s possessions will be multiplied by the percentage of minutes played to find the number of possessions in which the player was present.

The Block Percentage is instead the percentage of blocks made compared to the field shots attempted by the opponents. Like the Steal Percentage, it will be necessary to use the percentage of minutes played for the individual stat, in order to find the number of shots actually attempted by the opponents while the player was on the court.

The definitions already give an idea of what data we need; in any case, as always, I write them hereunder:

Team advanced stats

  • Team steals [TeSt];
  • Team blocks [TeBlk];
  • Opponent possessions [OppPoss];
  • Opponent field goals attempted [OppFGA];
  • Opponent 3-point shots attempted [Opp3PA];

Individual advanced stats

  • Player’s steals [St];
  • Player’s blocks [Blk];
  • Opponent possessions [OppPoss];
  • Opponent field goals attempted [OppFGA];
  • Opponent 3-point shots attempted [Opp3PA];
  • Minutes played [MP];
  • Team minutes played [TeMP];

Formulas and calculation

Team advanced stats

As you may have guessed, these formulas are quite simple. Let’s start with the team ones.

The formula for team Steal Percentage:

\boldsymbol{TeSt\%=\frac{TeSt}{OppPoss}\cdot 100}

Just divide the number of steals by the opponent’s possessions. To find that value, we have to use the usual formulas described in the related chapter of Learn a Stat.

Instead, for team Block Percentage:

\boldsymbol{TeBlk\%=\frac{TeBlk}{OppFGA-Opp3P}\cdot 100}

In the Block Percentage formula, 3-point shots are not taken into consideration: at the time of its creation, it was very rare to see a 3-point shot blocked.
Even today, almost all the blocks occur near the rim, although there has been an increase of 3-point shots and the close-outs are much more aggressive; if this trend continues, we could begin to consider including 3-point shots in this formula. For now, the incidence of 3-point shots blocked remains low and therefore negligible.

Individual advanced stats

The individual statistics use the same formulas as the team statistics, but with the addition of the percentage of minutes played.

Let’s start with individual Steal Percentage:

\boldsymbol{St\%=\frac{St}{OppPoss\cdot \frac{5\cdot MP}{TeMP}}\cdot 100}

Also in this case (as seen for several other statistics), the ratio between minutes played and team minutes played is used to estimate the number of possessions in which the player was present. This operation is necessary only when the calculation is done with data taken from the classic box score.

Lastly, the individual Block Percentage:

\boldsymbol{Blk\%=\frac{Blk}{\left (OppFGA-Opp3P \right )\cdot \frac{5\cdot MP}{TeMP}}\cdot 100}

As always, the percentage of minutes played allows us to find an acceptable number of shots attempted by opponents while the player was on the court.

How to read and analyze

Steal and Block Percentage are statistics easy to understand, once the formula is learned. The higher the value, the better the team or player in that aspect. The peculiarity of these statistics is once again to be not influenced by the game speed and they are evaluated on a common basis, that is the 100 possessions.

This Learn a Stat ends here. See you soon, your friendly neighborhood Cappe!

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