Previewing the 2019 NBA Draft: Remember, Grades are Not Destiny

What follows is a guest post from Professor David Berri. You might remember him as the creator of the Wins Produced metric, author of "Wages of Wins" and "Stumbling on Wins," and tenured professor of economics at Southern Utah University. Dave has done extensive work in studying the NBA draft and brings us his overview of this year's draft class. 

Update: Below Dr. Berri provided a grade based on the performance we saw. Others try and predict future performance. As Dave notes, this is harder, and even those that do it agree. Regardless, for those looking for a "draft board" Arturo Galletti has put up such a model on his site.

At the end of every semester in each of my classes, I assign grades.  The choices are A, B, C, D, and F.  Although most of my students pass, a few don't do well and fail (very few!).  Regardless of where the students end up, it is important -- as I often tell students -- to keep grades in perspective.  Yes, there is a tendency for people who do well in school to do well.  But grades are most definitely not destiny. Many "A" students do not end up being particularly successful in life.  And there are many students who do relatively poorly in school that have amazing lives.  

The same basic approach should be taken to evaluating how well NBA draft prospects in 2019 performed in college this past year.  These players took a college class this past season.  In this class, these players were evaluated in terms of shooting efficiency, rebounds, turnovers, steals, etc... (i.e., the factors that primarily create wins in basketball).  With data in hand, the number of wins each player produced per 40 minutes played (Wins Produced per 40 minutes or WP40) was calculated.  And this stat was then used to assign each player a grade in their respective college class.

Again, it is essential to remember that just like a college class, grades do not predict the future perfectly.  Yes, there is a statistical correlation between college performance and NBA performance (i.e., if you play poorly in college, you tend not to be a great NBA player). But college performance is not a crystal ball.  A bad grade could mean a player isn't particularly good.  But it could also mean the player wasn't healthy enough to perform well in class.  Or it could mean the teacher (i.e., the coach) wasn't very good.  Or maybe the player didn't try as hard as they could and with a bit more motivation performance could be much better.

The same story can be told about players who get a good grade.  Yes, maybe this means the player is great.  But it might mean the class they took wasn't particularly hard.  For example, maybe the competition the player faced wasn't very good.  Or maybe physically this player was able to over-power their opponents (something that won't happen in the NBA). 

In sum, if your favorite teams drafts a player with a "bad" grade, that doesn't mean your team drafted a "bad" player.  It probably means there are some issue to address. But it doesn't mean there is no hope.

Likewise, we shouldn't put the "A" players in the Hall-0f-Fame just yet.  Most of these players are not going to be All-Stars.  Most NBA players are not "great," and therefore, most players who are drafted won't be "great" either. So, if you are comparing the players drafted on Thursday night to NBA All-Stars you should expect some people to make fun of you.  At least you shouldn't be surprised when this happens. 

Okay, with all that being said, let's get to the grades.  The scale for the grades was determined by looking at how the players who were drafted out of college from 2009 to 2018 performed their last year in college.  Across this sample of 470 players, the average WP40 was 0.188.  An average player in college will produce 0.100 wins per 40 minutes.  So, an average player drafted out of college was quite a bit better than an average college player. 

Of course, relative to the average player drafted out of college, a player with a 0.188 WP40 was.... well, average.  And if we follow a typical grading scale, an average student is a "C" student.  

We can also use the data from 2009 to 2018 to determine the WP40 necessary to achieve each letter grade.  These ranges (and this is not how I grade in class!) were determined by simply breaking this sample into quintiles.  So the letter "A" goes to players in the top 20%, letter "B" to the next 20%, etc...

  • Range for "A" player (top 20% of players): WP40 above 0.245
  • Range for "B" player: 0.206 WP40 to 0.244 WP40
  • Range for "C" player: 0.169 WP40 to 0.205 WP40
  • Range for "D" player: 0.126 WP40 to 0.168 WP40
  • Range for "F" player (bottom 20% of players): WP40 below 0.126

Given these ranges, here are the grades each prospect for the 2019 draft received.

The "A" Players College Year Conference Minutes Wins Produced WP40
Zion Williamson Duke Fr ACC 988 10.6 0.431
Brandon Clarke Gonzaga Jr WCC 1039 10.1 0.391
Ja Morant Murray St. So OVC 1205 10.7 0.356
John Konchar Purdue Fort Wayne Sr Summit League 1131 9.9 0.349
Bruno Fernando Maryland So Big Ten 1019 7.2 0.284
Dylan Windler Belmont Sr OVC 1094 7.7 0.281
Bol Bol Oregon Fr Pac-12 267 1.9 0.281
Cody Martin Nevada Sr MWC 1170 7.6 0.260
Grant Williams Tennessee Jr SEC 1181 7.6 0.257
Justin Robinson Virginia Tech Sr ACC 712 4.6 0.257
Shamorie Ponds St. John's Jr Big East 1158 7.4 0.256
Jaxson Hayes Texas Fr Big 12 747 4.7 0.251
Juwan Morgan Indiana Sr Big Ten 1043 6.4 0.246

Zion Williamson was the top player -- per 40 minutes -- in college basketball this past year. In fact, he is one of the most productive college players this century.  But we must remember that being the best student in class doesn't guarantee that you will be the most successful person in life.  College basketball is not the same as the NBA.  So, it is possible Zion Williamson will not become a Hall-of-Fame player for the New Orleans Pelicans.

A similar story can be told about Ja Morant.  He actually produced more wins than Williamson.  But that does not guarantee Morant will be an NBA All-Star.

The "B" Players College Year Conference Minutes Wins Produced WP40
Cameron Johnson North Carolina Sr ACC 1078 6.6 0.244
Ty Jerome Virginia Jr ACC 1257 7.6 0.242
Tacko Fall UCF Sr AAC 818 4.9 0.242
Chuma Okeke Auburn So SEC 1105 6.6 0.241
Matisse Thybulle Washington Sr Pac-12 1121 6.5 0.232
Charles Bassey Western Ky. Fr C-USA 1068 6.1 0.229
Zylan Cheatham Arizona St. Jr Pac-12 1100 6.3 0.229
Ethan Happ Wisconsin Sr Big Ten 1087 6.2 0.229
Paul Reed DePaul So Big East 966 5.4 0.225
Daniel Gafford Arkansas So SEC 919 5.1 0.221

As I tell students, "B" means "good." So, there is nothing wrong with being a "B" player (or a "B" student).

Tacko Fall is an interesting "B" player.  Right now he isn't projected by ESPN to be drafted.  But he did produce in college, and he is 7-6.  It will be interesting if any team takes a chance on him.  There is some evidence that being tall in basketball helps. 

Okay, enough of the "good" and "great" player in the class.  Here are all the students who didn't do so well. 

The "C" Players College Year Conference Minutes Wins Produced WP40
Jarrett Culver Texas Tech So Big 12 1238 6.3 0.205
PJ Washington Kentucky So SEC 1024 5.2 0.203
Tremont Waters LSU So SEC 1071 5.4 0.201
Aric Holman Mississippi St. Sr SEC 830 4.1 0.197
Dean Wade Kansas St. Sr Big 12 760 3.7 0.194
Dedric Lawson Kansas Jr Big 12 1177 5.7 0.193
Jared Harper Auburn Jr SEC 1315 6.3 0.192
De'Andre Hunter Virginia So ACC 1235 5.8 0.187
Killian Tillie Gonzaga Jr WCC 249 1.1 0.183
Mfiondu Kabengele Florida St. So ACC 799 3.6 0.181
Darius Garland Vanderbilt Fr SEC 139 0.6 0.179
Jaylen Hands UCLA So Pac-12 1029 4.4 0.173
Devon Dotson Kansas Fr Big 12 1167 5.0 0.171
Quinndary Weatherspoon Mississippi St. Sr SEC 1158 4.9 0.171
Nickeil Alexander-Walker Virginia Tech So ACC 1165 5.0 0.170
Rui Hachimura Gonzaga Jr WCC 1115 4.7 0.169
The "D" Players College Year Conference Minutes Wins Produced WP40
Sagaba Konate West Virginia Jr Big 12 192 0.8 0.168
Jaylen Nowell Washington So Pac-12 1243 5.2 0.166
Tyler Herro Kentucky Fr SEC 1207 4.9 0.162
Terence Davis Ole Miss Sr SEC 1023 4.1 0.161
Nicolas Claxton Georgia So SEC 1011 3.8 0.150
Miye Oni Yale Jr Ivy League 900 3.4 0.150
Isaiah Roby Nebraska Jr Big Ten 1095 4.0 0.146
Kerwin Roach II Texas Sr Big 12 904 3.3 0.145
Justin Wright-Foreman Hofstra Sr CAA 1321 4.7 0.142
Keldon Johnson Kentucky Fr SEC 1137 3.9 0.138
Ky Bowman Boston College Jr ACC 1219 4.1 0.136
Jarron Cumberland Cincinnati Jr AAC 1136 3.8 0.133
Jordan Poole Michigan So Big Ten 1220 4.0 0.132
Coby White North Carolina Fr ACC 997 3.3 0.131
RJ Barrett Duke Fr ACC 1342 4.3 0.128
The "F" Players College Year Conference Minutes Wins Produced WP40
Romeo Langford Indiana Fr Big Ten 1094 3.4 0.125
Ayo Dosunmu Illinois Fr Big Ten 994 2.8 0.114
Ignas Brazdeikis Michigan Fr Big Ten 1099 3.1 0.113
Nick Ward Michigan St. Jr Big Ten 708 2.0 0.111
Kevin Porter Jr. Southern California Fr Pac-12 463 1.3 0.110
Lindell Wigginton Iowa St. So Big 12 649 1.7 0.104
Charles Matthews Michigan Sr Big Ten 1069 2.8 0.104
Jordan Nwora Louisville So ACC 1086 2.8 0.103
Jalen McDaniels San Diego St. So MWC 1057 2.6 0.099
Max Strus DePaul Sr Big East 1310 3.2 0.098
Eric Paschall Villanova Sr Big East 1300 3.1 0.096
Charlie Brown Saint Joseph's So Atlantic 10 1139 2.7 0.095
Jaylen Hoard Wake Forest Fr ACC 934 2.2 0.094
Admiral Schofield Tennessee Sr SEC 1176 2.7 0.091
Tyus Battle Syracuse Jr ACC 1163 2.5 0.085
Tyler Cook Iowa Jr Big Ten 1019 2.1 0.084
KZ Okpala Stanford So Pac-12 950 1.9 0.082
Talen Horton-Tucker Iowa St. Fr Big 12 950 1.9 0.079
Louis King Oregon Fr Pac-12 941 1.5 0.063
Nassir Little North Carolina Fr ACC 652 1.0 0.063
Milik Yarbrough Illinois St. Sr MVC 967 1.5 0.061
Luguentz Dort Arizona St. Fr Pac-12 1074 1.6 0.060
James Palmer Nebraska Sr Big Ten 1266 1.8 0.058
Markis McDuffie Wichita St. Sr AAC 1236 1.7 0.056
Naz Reid LSU Fr SEC 925 1.1 0.048
Jarrey Foster SMU Sr AAC 370 0.3 0.037
Simisola Shittu Vanderbilt Fr SEC 854 0.8 0.037
Quentin Grimes Kansas Fr Big 12 989 0.9 0.035
Carsen Edwards Purdue Jr Big Ten 1277 0.8 0.025
Kris Wilkes UCLA So Pac-12 1047 0.6 0.022
Cam Reddish Duke Fr ACC 1070 -0.8 -0.031

The "C", "D" and "F" player were not "great" in college.  They took the class. But relative to other players selected in the NBA draft in the past ten years, these players did not do "great' this past season. Again, this doesn't mean they won't be great NBA players. 

Interestingly, Duke had the very best player in the class (Zion Williamson) and then two players who didn't do so well.  R.J. Barrett was the worst of the "D" students.  In other words, he barely passed.  And Cam Reddish... well, no one drafted in the past ten years played as badly as Cam Reddish this past season.  So, at this point, we know Barrett and Reddish were not great college players.  But again, there are many reasons a student doesn't do well in a class.  So, maybe both of these players can become great NBA players (of course, then again, maybe they won't).

In the end -- as I said earlier -- there is just a correlation between college performance and NBA performance.  It is not a perfect crystal ball.  It probably would help to look at more than just performance in class and think about how a player's game would translate to the NBA.  Of course, when you do this, you should ask: "Are the factors you are looking at beyond college performance correlated with NBA performance? And how do you know this?"

Perhaps these non-performance factors you are looking at are important.  However, if they are telling you that the player you are looking at is definitely a future Hall-of-Fame player... you probably should try looking a little harder.

Reminder, in case you read the whole article but skimmed the intro, this was produced by Dr. David Berri. Please send any praise his way either in the comments or on Twitter @wagesofwins! Also, follow @AmericanNumbers on Twitter will be providing great draft analysis I'm sure.