The Eddy Curry ConundrumBy Kevin Pelton
Feb. 4, 2004
Believe it or not, I was actually excited to see the Chicago Bulls bring their 13-35 record to KeyArena earlier this week. One of the major reasons was getting a first-hand look at Bulls center Eddy Curry, who's become quite an interesting player to me statistically.
No, this is not like the age-old lament about Curry - how can a guy that big be such a poor rebounder? Instead, Curry is fascinating to me as the personification of my questions about the validity of statistics. Just a year after leading the NBA by shooting 58.5% from the field, Curry has hovered around 50% this season -- not far above league average for a center -- before getting to 51.1% with a recent hot streak (including 25 points on 10-for-15 shooting against the Sonics).
Imagine Ichiro following up his rookie batting title by hitting .280, or Michael Jordan dipping to 18 points per game during his third season. These notions are ridiculous, but Curry has done something similar -- if in a less important statistical category -- and the average fan hasn't even batted an eye, buying Scottie Pippen's argument that it's just a case of his younger teammates not working hard enough.
Sorry, but that won't do it for me. Was Curry's performance predictable? Where is he going in the future? And what does that tell us about basketball statistics in general?
Mini-Study 1: Was Curry's FG% drop predictable?The first thing I took a look at here was the performance of other players who have shot as well as Curry, specifically looking at two-point percentage. Curry's two-point percentage was a full standardized deviation above league average last season. I looked at the ten players directly above and below him in terms of standardized two-point percentages (minimum 500 minutes).
On average, these players saw their standardized two-point shooting drop off by about 13.5%. If we apply this average to Curry, he could reasonably be expected to shoot about 54.8% from two this season. There have been players, however, who have declined as much or worse. Four of the 20 did, including a pair of players who were top two-point shooters in 2001-02 -- Brent Barry and Darvin Ham. After shooting 58.8% and 56.9%, respectively, from two that season, they dropped off to 51.4% and 45.7% last year.
There was something important these players shared in common. The year before their outstanding two-point shooting, they had not been nearly as good, Barry shooting 51.7% and Ham 48.8%. Lo and behold, Curry shot just 50.1% from the field as a rookie. Perhaps it's not this season that is the fluke, but last year?
That inspired another study. I looked at the players who made the most improvement in two-point percentage after being league average or better the year before. Curry showed up 17th on this list, and I also found another player whose progression is interesting to me, New Orleans (All-Star) center Jamaal Magloire. Magloire went from shooting 45.1% as a rookie to 55.1% in 2001-02 to 48.0% last year to 46.0% this year.
All told, I looked at 15 players. On average, the group averaged 48.3% two-point shooting in Year 1, which leaped to 56.7% in Year 2. And Year 3? They dropped to 50.3%, scarcely better than they had done in Year 1. On average, they lost 11.3% of their two-point percentage from Year 2 to Year 3. (Curry has been right about average, losing 12.6% so far.)
Really, should this surprise us? No, it probably shouldn't. Good ole' regression to the mean implies that players who improve a lot have probably been lucky to some extent or another and will see that luck turn the next year. On an overall level, John Hollinger has found rather conclusively in his Pro Basketball Prospectus series that players who have what he terms "fluke years" -- substantial increases in Hollinger's PER rating at age 27 or later -- almost always come back to their previous level the next year.
Loose, weakly-supported conclusion: Curry will always be a good shooter, but it's improbable he ever hits 58% from the field again.
Here's another interesting thing about Curry: He's been a much better performer in the second half of the season than in the first half in both of his first two NBA seasons. After all, a year ago people were calling Curry a disappointment too. It was only in the second half that he stepped up to 14.7 points per game and incredible 61.3% shooting.
Combining the two years, Curry has gone from 5.1 points and 2.8 rebounds per game on 47.4% shooting in the first half to 12.0 points and 5.3 rebounds on 58.5% shooting.
That leads us to another mini-study, formalizing an idea I've floated before, most recently when discussing Kwame Brown in a column last week.
Mini-Study 2: Which is a better future predictor, second-half performance or overall performance?Every statistician's favorite Web site, DougStats.com provides second-half only stats for the last two years. I ignored the 2002-03 splits, solely because this season is still ongoing. Instead, I focused on the 2001-02 second half, calculating my efficiency rating both overall and for the second half only for players who played at least 250 minutes in both halves of the season and 500 minutes in 2002-03.
My first method of comparison was to look at the correlation between the two 2001-02 efficiencies and the 2002-03 efficiency. Correlation isn't an exact measure of predictive ability, but with a sample size of 226 people, it's a good place to start. The correlation between overall 2001-02 efficiency and 2002-03 efficiency is pretty high -- .7577. When we go to second-half efficiency, it drops to .6945.
Another way to look at predictive ability is to do so literally -- see which is closer to the player's 2002-03 efficiency, his overall or second-half efficiency. Here, the evidence rather overwhelmingly favors the overall numbers. Only 86 of the 226 players (38.1%) had their performance predicted better by their second-half performance.
Okay, so overall performance is a better predictor when we consider all players. However, we'd never look specifically at the second half for players who played the same. Our real interest lies with players whose performance changed, primarily for the better. Let's isolate the players who improved the most in the second half.
Sticking with the 2001-02 season, there were 12 players whose second-half efficiency rating was at least 25 points better than their overall rating. Looking specifically at these players has mixed results. The correlation is higher with second-half performance (.635 vs. .451), but the overall numbers are better predictors, coming closer to nine of the 12 players' 2002-03 performance.
Even here, there is the opportunity to reduce the sample. If a veteran player has a fluke 41-game stretch, that doesn't surprise anyone, but we believe that when a young player plays better during the second half, it means he's actually improving. There were ten guys under age 25 who improved at least 20 points, and half of them had their 2002-03 performances predicted better by the second half, including the four youngest players (Eddy Curry, Kwame Brown, Richard Jefferson, and Corey Maggette). The second-half correlation was also better.
Loose, weakly supported conclusion: Perhaps it is worthwhile to look at second-half upgrades -- but only for a limited number of young players, and even then the difference has to be significant. And if a 41-game improvement often doesn't mean that much, that's more than doubly true about a good month, like those had in January by Brown and Phoenix's Joe Johnson.
Where does all that leave Curry? After consecutive 20-point efforts in his last two games (he preceded his 25 points against the Sonics with a season-high 27 at Portland), he looks like he could be beginning another second-half surge. If there are players who consistently improve their games in the playoffs, why can't there be those who are consistently better in the second half of the season?
If Curry does have another second-half surge, I won't be so confident next season that it will translate into improved performance over the course of entire season (having already called him a "breakout candidate" two times too many).
I do expect his field-goal percentage to continue to edge up. While players have seen similar declines, 74 points is still a lot of shooting to lose. An improvement will be huge for Curry, since so much of his value is in his ability to score efficiently in the post. When people say he's had a disappointing season, they are clearly referring to his shooting, since his rebounding isn't that different and his scoring average is up.
There are many chapters left to be written in the book of Eddy Curry's NBA career. Like any good story, I can't wait to turn the page and see what's in store.
Kevin Pelton is an intern for the Seattle SuperSonics and is responsible for original content on Supersonics.com. He writes "Page 23" for Hoopsworld.com on a semi-regular basis. He can be reached via e-mail at firstname.lastname@example.org.