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NBA Draft Efficiency

FOR OVERALL LOGISTIC REGRESSION ANALYSIS CLICK HERE.

FOR BIG EAST CONVERSION RATES CLICK HERE.

FOR BIG TEN CONVERSION RATES CLICK HERE.

FOR BIG TWELVE CONVERSION RATES CLICK HERE.

FOR SEC CONVERSION RATES CLICK HERE.

FOR PAC-12 CONVERSION RATES CLICK HERE.

FOR NON-BCS CONVERSION RATES CLICK HERE.

The NBA Draft can be a time for college basketball fans to cheer about the “success” of their basketball program.  Kentucky, Duke, North Carolina, and Kansas fans can boast about the number of alums currently in the NBA.  This year, ESPN is taking that discussion one step farther by describing the quality of NBA players produced, and ranking the “NBA Pedigree” of colleges.

Our take is a bit different as we will examine the process of taking high school talent and converting it into NBA draft picks. In other words, we want to understand how efficient are colleges at transforming their available high school talent into NBA draft picks? Today, we launch our NBA draft series by ranking the schools in the ACC based on their ability to convert talent into draft picks.

The initial approach is fairly simple.  Each year, (almost) every basketball program has an incoming freshman class.  The players in the class have been evaluated by several national recruiting/ranking companies (e.g. Rivals, Scout, etc…).  In theory, these evaluations provide a measure of the player’s talent or quality*.  Each year, we also observe which players get drafted by the NBA.  Thus, we can measure conversion rates over time for each college.  Conversion rates may be indicative of the school’s ability to coach-up talent, to identify talent, or to invest in players.  These rates may also depend on the talent composition of all of the players on the team.  This last factor is particularly important from a recruiting standpoint.  Should players flock to places that other highly ranked players have selected?  Should they look for places where they have a higher probability of getting on the court quickly? Next week we will present a statistical analysis (logistic regression) that includes multiple factors (quality of other recruits, team winning rates, tournament success, investment in the basketball program, etc…). But for now we will just present simple statistics related to school’s ability to produce output (NBA draft picks) as a function of input (quality of recruits).

Our first set of rankings is for the ACC.  At the top of the list we have Boston College and Georgia Tech.  Boston College has done a good job of converting low-ranked talent into NBA picks (in this time period they had two three-star players and a non-rated player drafted).  Georgia Tech, on the other hand, has converted all of its five-star recruits, and several of its four-star recruits.  A result that may at first glance seem surprising is the placement of UNC and Duke.  However, upon reflection these results make a good deal of sense.  When players choose these “blue blood” programs they face stiff competition for playing time from both current and future teammates.

Here are some questions you probably have about our methodology:

What time period does this represent?

We examined recruiting classes from 2002 to 2011 (this represents the year of graduation from high school).  While the chart above ranks the ACC, we compiled data for over 300 Division 1 colleges (over 12,000 players).

How did you compute the conversion rate?

The conversion rate for each school is defined as (Sum of draft picks for the 2002-2011 recruiting classes)/(Weighted Recruiting Talent).  Weighted Recruiting Talent is determined by summing the recruiting “points” for each class.  These “points” are computed by weighting each recruit by the overall population average probability of being drafted for recruits at that corresponding talent level.  We are using ratings data from Rivals.com.  The weights for each “type” of recruit were 0.51 for each five star recruit, 0.13 for each four star, 0.03 for each three star, 0.008 for each two star, and 0.004 for each not ranked.  

Second-round picks often don’t even make the team.  What if you only considered first round picks?

We have also computed the rates using first round picks only, please see the table below.

*We can already hear our friends at Duke explaining how players are rated more highly by services just because they are being recruited by Duke.  We acknowledge that it is very difficult to get a true measure of a high school player’s ability.  However, we also believe that over the last ten years, given all of the media exposure for high school athletes, this problem has attenuated.

 

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