Every year, it seems like One & Done prospects dominate the buzz surrounding the NBA Draft. But do they perform better than their peers who spend multiple years in college or come from overseas?
I will analyze players who have been drafted between 2007 and 2014 and look at their performance up until the end of the 2014 NBA season. To measure their performance in the NBA, I will use the advanced metric "Win Shares per 48 Minutes", which determines how much a player contributes to a given win. You can read more about this metric here and here.
First off, it is important to see where these One & Done prospects get drafted to be able to compare them to their peers who were drafted in similar positions. The chart below is a breakdown:
From 2007-2014, 67, or 14% of all drafted players, have been One & Dones. As you can see from the chart above, the majority of them get picked early in the draft. Sixteen One & Dones have been picked in the Top-3 and only 9 have been selected in the 2nd round.
Below is a chart which breaks down how they perform in the NBA using the WS/48 metric. From here on out, I excluded players who who have played less than 20 NBA games from my analysis since their WS/48 is often skewed due to small sample size.
Although One & Dones drafted in the Top-10 perform relatively well, if not better than their peers, those drafted past the 10th pick perform significantly worse than their peers both in their rookie seasons and careers.
It is interesting to see that some of the conventional wisdom about NBA draft prospects is indeed true when it comes to picks 11-60:
-One & Dones who aren't projected to be top picks are not be ready for NBA; they might have been better off staying in college for longer
-Prospects who have played multiple years of college basketball are more "NBA ready" as they outperform their peers in their rookie seasons
-International players do seem to need more time to adjust to NBA basketball. They outperform their peers in their careers despite sub-par performances their rookie seasons
Below is another chart which compares draft position to WS/48, where each point represents a player:
Assuming players with a career WS/48 below 0.0153 (standard deviation) are "draft busts", One & Dones would have an alarmingly rate of busts despite their favorable draft positions. 19% of all One & Dones end up becoming busts, where as it's 14% for 2+ years of college players and 12% for international players.
If a player with a career WS/48 of above 0.1256 (standard deviation) is considered to be a successful draft pick, Top-3 draft picks who spent multiple years in college have a better "success rate" (43%) than One & Dones (25%).
That being said, overall, One & Dones do have a higher ceiling. 23 players drafted between 2007-2014 have been selected to All-Star games. Of those 23, 9 are One & Dones (that's 39% of all All-Stars, despite only representing 14% of all draft picks), 13 are 2+ years of college players and 1 is an International player.
Although WS/48 is an excellent way to measure performance, there are some caveats to using solely this statistic as a way to judge a NBA player's performance. Below are the top WS/48 players drafted between 2007 and 2014.
Although there are many familiar names on this chart who deserve to be mentioned as top NBA players, the shortcomings are obvious. For example, it's difficult to argue that there are 9 players drafted in this time who have performed better than reigning MVP Steph Curry, especially when you see names like Tiago Splitter and Brandan Wright ranked right above him.
I also wanted to include the number of draft picks who are out of the league in my analysis, but unfortunately, based on the data available, it is impossible to identify which players are currently out of the NBA.
That said, if I were a GM, based on this analysis, I would be cautious drafting One & Dones outside the Top 10.
Data Source: www.basketball-reference.com/