After last week’s column about the sustainability of shooting, I want to build on that foundation and steer my thought into new directions.

In that piece, I mentioned Derrick Rose’s league-leading field goal percentage on short shots (58.2 percent) and wondered whether that was something he could repeat in years to come.  While we’re not quite ready to make projections from the raw data, I was curious about a related question:

Do rookies tend to improve their shooting percentage in their sophomore year?

I touched on this topic before in this space but not across all the shot locations.  So, Rose has experienced an enormous jump on shots within ten feet and I wondered if that was an outlier compared to the rest of the rookies/sophomores in the sample.  So I gathered all the rookie/sophomore seasons of the past four years (the span of the Hoopdata set) and set some qualifiers.  To reduce variability in the analysis, I set the sample frame to 50 shot attempts in the shot location in both their rookie and sophomore season.  That way, Steve Novak can’t bring the noise.

I have some reservations about setting the bar at that level because quite honestly, 50 shot attempts isn’t a whole lot but I also recognize that, by and large, rookies rarely get the opportunity to get that many shots in the first place.  Set the bar too high and the chart looks at the development of Kevin Durant and Joakim Noah.  As a result, two biases exist here.  A selection bias arises because we’re only looking at the players who got enough run to get their shots and secondly, a survivor bias exists because players who shot poorly in their rookie year might not shoot enough to qualify in the second.  But nonetheless, this situation is more desirable than analyzing a couple of data points.

Just as I did in the last article, I charted each player’s year 1 and year 2 field goal percentages from the following Hoopdata shot locations: at rim (layups, dunks, and tip-ins), short (<10 feet), mid (10-15 feet), long (16-23 feet), and three-pointers.  In this study however, the year 1 will always be the rookie season and year 2 will be the sophomore season.

Let’s take a look at how rookies performed on at rim shots in their first two years in the league.  Did rookies get better with a year of NBA play under their belt?

Of the 65 rookies in the sample, 32 improved their at rim field goal percentages the following year as you can see by the data points below the gray diagonal.  Surprised?  Well, before you conclude that all rookies will get worse at finishing layups in the following year, remember that 33 vs. 32 is not a convincing defeat by any means.  The average change in field goal percentage was actually a positive 0.006 or 0.6% but insignificantly so.

Still, for those expecting an general increase in ability to finish at the rim, this is a bit of a surprise.  When we break this down into positions, we find that 9 of the 13 point guards improved from rookie to sophomore year which is the best improvement of the five positions of the floor.  Interestingly enough, only 12 of the 27 big men in the sample (power forwards and centers) experienced an uptick in their success rate at the basket.

How about short shots? Where does Derrick Rose’s mark fit in?

In this sample, Derrick Rose and Rajon Rondo improved the most. Where can you find them? Rondo’s the southernmost point on the chart whereas Rose finds himself furthest east.  There were only 21 rookies in this sample so the conclusions are quite limited.  For what it’s worth, two-thirds of this sample improved into sophomore year but with such a small sample size, that’s easily due to random chance. In my study last week, I found that year-to-year correlations were the most random in this zone.  Brandon Roy and O.J. Mayo, both shooting guards (or hybrids in many situations) both declined in sophomore year from this range.  This area generally has the least focus among basketball players so a decline usually is nothing more than a tiny dent in production.

Moving on to the 10-15 feet shot which we can the mid-range.

With only 16 players who fit the criteria in this shot zone, the relationship looks to be completely random.  Some improved and some regressed.  LaMarcus Aldridge went from a 29.0 FG% shooter from the 10-15 foot range in his rookie year to one of the most successful mid-range shooters in the game in his second year.   His struggles in his rookie year didn’t discourage him as only six players took more shots from this area per game the following year and his field goal percentage soared to 45.3 percent.  Teammate Brandon Roy didn’t enjoy the same success, however. He shot a blistering 45.4 percent his rookie season and fell to 31.3 percent in his sophomore campaign.  Unfortunately, the tiny sample size doesn’t allow us to extrapolate much from this area.

What about long twos? Have sophomores shoot better just inside the three point line?

Like the mid-range shot, sophomores in this sample don’t seem to exhibit improvement on long twos.  Of course, this area of the floor probably is most sensitive to the biases since not every player possesses enough of this shooting skill to qualify.  Especially with bigs, the mid-range jumper is work in progress for the first couple years in the league.

Among the 11 shooting guards in the sample, only Randy Foye and Ronnie Brewer experienced more success on their long two jumper in their sophomore year. Aaron Afflalo, O.J. Mayo, Brandon Rush, Daequan Cook, and Eric Gordon all regressed following their rookie campaign.  In the case of Mayo, it was a regression to the mean after a sparkling rookie campaign where he shot 45.2 percent from 16-23 feet.  He’s about league average this season.  He’s not an exact comparable for Ty Lawson who’s shooting 48 percent this year but he should take note as most of the rookies who shot better than league average (40%) on long twos in their rookie year, ended up below the norm in year two.

How about the three-point line?  This is just the past four years but I’m sure longer studies have been done before.

Again, lots of randomness here but that’s to be expected with only 30 observations.  Half of the group declined and half improved their downtown shot.  The most stark correction came from Michael Beasley who shot 61.1 eFG% in his rookie year but just 40.2 eFG% this season.  This must be evidence of the curse of the No. 2 pick, right?  Actually, no.  2007 No. 2 pick Kevin Durant improved his three-point shot from 43.1 eFG% to 63.3 eFG% from year-1 to year-2.  That was a quick disposal.

So what did we learn? As much as we want to believe that “one year under the belt” theory, it hasn’t shone through in this crop of rookies.  If anything, we observe a regression to the mean as opposed to uniform improvement. There’s plenty more work to be done in this area and this certainly doesn’t wrap up the rookie to sophomore growth analysis.   As it is with a lot of basketball studies, we need more data to draw stronger conclusions.  The limited scope of shot location data keeps our extrapolation to a minimum.   But nonetheless, if you wonder if Ty Lawson’s 48 percent shooting from long two or Brandon Jenning’s putrid finishing ability are here to stay, you can refer back to these charts to see if past extraordinary rates continued the following year.