|Andrew Johnson: Curse Of The Mid Range Shooter
(And The Shooting Competence Curve)
Last October I unveiled my Scoring Versatility Index at Hickory High. The idea at the
time was to create an index that graded a player's efficiency scoring in a variety of
ways including from different spots on the court and from the line, with the theory
that a player efficient from more locations would be harder to guard.
The immediate problem that I found was that as one carves up the court into smaller
pieces one creates more data sets with smaller sample sizes, and the less reliable data.
It is a problem, as I have noted, with the shot chart era in general. Carving up the
court into pretty pictures can sometimes give us pretty unreliable impressions. Looking
to account for this has been an interesting challenge and lead me to a few somewhat
Players with only a few shots from any zone will have averages unreflective of their
'true' talent level, and, in fact, with three point shots the inherent high variability it
takes a fairly large number of shots to determine true talent with any confidence.
Statistics and a couple of assumptions can help us out here. Over a given period
players will shoot above or below their 'true' ability based solely on random variance
(compounded, perhaps, by opponent variation, injuries, confidence levels and so on).
It's a tried and true assumption that after these streaks, over the longer term the
player's shooting percentage will revert or regress toward their 'true' average, with
reversion taking longer with a higher variability.
That leaves open the question of what the player's true shooting ability.
My assumption also was that a player that rarely takes a three point shot is likely to
be a 'replacement' level three point shooter rather than an average one. That's
convenient for estimating the Versatility Index as crediting every player with average
percentages with few if any shots would not help in measuring difference in scoring
versatility. When I looked at the data is also happened to be true.
Using the NBA.com shot zone data I charted each of the NBA's five shot zones with
each player's shooting percentage against the number of shots taken in that zone. (The
zones are the restricted area, paint outside of the circle, mid-range, corner three and
above the break three). For the three jump shooting zones in the mid range and the
threes the pattern was pronounced, players who shoot more mid range jumpers, for
example, make them at a higher rate.
The number of attempts from the mid range conveys two pieces of information, the
amount of time the player is on the court and the degree of comfort the player and
his coach have in him shooting in the mid range, ie whether that is one his spots.
Contrary to some opinions coaches have some idea who their better players are and
players have some idea where they shoot better. The same is true of corner and
above the break three point shots.
Curses and Blessings
The problem, for mid range shooters, is that even for good mid-range shooters the
shot isn't terribly efficient. That can be seen in the image below along with the
increasing expected competence with more attempts via a logarithmic trend line.
Only the most efficient mid range shooters like Chris Bosh and Dirk Nowitzki approach
league average efficiency as measured by eFG% (the dotted line) from mid-range.
Players like Carmelo Anthony, DeMar DeRozen and LaMarcus Aldridge last year were
fairly good (and liberal) with a not good shot.
Via Ian Levy's work on Xpps, the average point per shot for mid-range attempt is .793,
or an eFG% of 39.6%. The competence curve on mid range shots last year indicates
that players who attempted fifty to sixty mid-range shots were more likely to average
near 36%, while players with just over 150 attempts the expected competence is closer
to league average and high volume mid-range shooters the curve rises to only 42% to
In contrast, most of the more prolific shooters of the above the break on the three hit
for above average efficiency. And we also see the same increasing competence curve,
leaving players on the right side of the image taking a allot of an efficient shot and
being pretty good at it...CONTINUE READING AT COUNTING THE BASKETS