The young and talented Duke Blue Devils finished the 2022-2023 season battered and bruised.  Tennessee treated the Duke Blue Devils like the Detroit Pistons handled a rising Michael Jordan.  Tennessee threw elbows, closed the space between Duke’s offense and Tennessee’s defense and manhandled Duke to 65-52 defeat.  

To close out the regular season, Duke was playing well.  Their talent and playing style led pundits to pick Duke as a favorite for the national championship but talent and a pretty playing style were trumped by physicality.  

The 2023-2024 Duke Blue Devils will be led by Kyle Filipowski and Jeremy Roach.  Roach returns for his senior year and is a seasoned vet.  Filipowski opted to return to Duke instead of going to the NBA after his freshman campaign. Filipowski will be joined by fellow sophomores Tyrese Proctor and Mark Mitchell.  

Duke’s roster will receive its usual influx of Freshman talent with 5 star guards Jared McCain, Caleb Foster and 5 star forwards Sean Stewart and Jaylen Blakes. 

The talented roster will not diminish the comparisons of head coach John Scheyer to hall of fame legend Mike Krzyzewski.  Coach K’s shadow will loom long over the program and at this point it is difficult to say if Duke hired the right man to replace Coach K.  The standard at Duke is no different than at any other blue blood and until Scheyer wins a national championship or consistently makes  Elite Eights and Final Fours, the comparisons and the expectation will be set by Coach K’s success.  

None of this is new but to preview the 2023-2024 season we have to look at the past and analyze what Duke is used to under Coach K and what happened during John Scheyer’s first season as head coach.  

There should also be more pressure and a much higher expectation this season than last season because Scheyer was able to keep Filipowski from going pro.  The 2023-2024 Duke team is talented and experienced.  Scheyer should be able to get off the blocks faster and have a better pulse on the team and its capabilities because of the quality of returning players.  

A dependency on the one and done has meant that the first months of the season require installation.  Practices are slower, there is more talking and teaching than action.  Experience minimizes the installation period because experience means that there are more coaches on the floor.  Duke should not lack leadership with players like Roach and Filipowski.  There should be more voices and more teaching by the players.  

Experience should allow John Scheyer and the staff to be a bit less hands on and maximize reps when compared to last year.  Talent and experience also allows for Duke to be more dependent on a system based offense and defense than calling out sets.  Scheyer should be able to go to a more read and react method of playing if he wants to.  The evaluation should focus on fine tuning.  Does Scheyer and his coaching staff have the ability to pay attention to detail to identify problems and fine tune?  The problems should be less glaring and obvious with a veteran team.  It is much easier to identify the deficiencies and weaknesses of a young team than a veteran team.  What makes this job more difficult are the expectations and the pressure and that outside intensity can get to players and coaches and make it difficult for a coach to push the right buttons.  As an example all one needs to do is look at what happened to last year’s North Carolina team. North Carolina was a preseason number one team and failed to make the NCAA tournament.  

PLACES OF IMPROVEMENT

Figure 1 demonstrates the difficulty of transitioning to a new head coach with a young roster.  The 2022-2023 season had the third lowest net rating in the last ten years.  Comparing John Scheyer’s first season with Coach K’s last, the 2021-2022 Duke Blue Devils net rating towers over the 2022 season.  

The net rating is explained by a drop in offensive rating and a slight increase in defensive rating from the 2021-2022 season.  

To be fair to Scheyer, Coach K’s offensive rating in 2021-2022 was higher than the previous three seasons and the defensive rating was lower than the 2020-2021 season. 

A positive sign is that the defensive rating did not balloon.  An explosive  increase in defensive rating would be a clear indicator that Scheyer is in over his head.  A staple of Duke’s identity is defense.  There are spikes in Duke’s defensive rating in Figure 2 but the majority of the seasons Duke maintains a defensive rating below 100.  

Duke’s defensive rating in 2022 is below 100.  Scheyer emphasized defense in his interviews and the 2022 team defended well.  Duke lost Dereck Lively to the NBA draft and his ability to defend the rim was a big factor in Duke’s defensive efficiency.  Duke will have to scheme more and depend on its perimeter defense to protect the rim in 2023.  Duke’s defensive efficiency in 2023 will be a big indicator in determining the quality of Scheyer’s coaching.  

Figures 1 and 2 provide a high level analysis of metrics by comparing them with previous seasons.  Figure 3 focuses on the 2022-2023 season by examining effective field goal percentage.  The line plot and the density plots focus on pre-conference games and conference games.  Post-season conference tournament data is not included in the plots. 

The spacing of the lines in the line plots differs in November and December from January to March.  The line plot at the beginning of the season resembles an earthquake seismic reading.  The shift from peaks to valleys is steep and tight when compared to conference games.  A possible  conclusion is that effective field goal percentage was more consistent during conference play and more volatile at the beginning of the season but we will look at measures of central tendency and dispersion before we make this conclusion..

The density plots for pre-conference games and conference games in the 2022-2023 season have a similar mean.  The distribution of the data is different.  The density plots in the pre-conference tournament have a thicker shape and high frequency but the drop off is much higher than the decline in conference games.  Pre Conference EFG skews to the left and Conference EFG skews to the right.  The density plots seem to confer that conference EFG appears to be less volatile and more consistent than EFG for pre-conference games.  

MEAN IS FOR THE PLAYERS

With a data set that is skewed and does not have a gaussian distribution, the median is a better method of analysis because the median is not affected by outliers like the mean.  In the next set of visualizations we continue to explore effective field goal percentage.  The mean and the variance will support the conclusion that Duke’s shooting became more consistent and was less volatile.  The median however was lower during conference games than pre-conference games. 

Duke was playing better basketball at the end of the year but Duke was not shooting the ball more efficiently.  

Data analysis is important because it can present two different arguments that are supported by facts.  The mean and variance point to one direction.  The median refutes that conclusion.  From a coaching perspective what should matter to the coaching staff is the truth.  The truth is that Duke was not as efficient with its shooting during conference games.  Understanding this fundamental truth helps the coaching staff to clearly identify where it should look to improve during the offseason.  As a coaching staff, you take the worst statistics and metric and you use that to motivate yourself and to improve.  In this case the worst statistic is the truth.  The data is impacted by outliers and the mean and variance are affected by the outliers.  

However, the information you can present to the team can be different from the truth if it will generate confidence.  

Belief is important in sports.  Belief is important to a team, especially to a young team.  

The concept of belief is beautifully portrayed in Ted Lasso.  One of the most emotional and moving moments of the show is at the end of season 3 when the  players reach into their lockers, books, captain bands and socks and pull out the pieces of the torn BELIEVE sign.   A team united itself around an idea and even when that physical reminder of that idea was destroyed, the players refused to give up on that idea, on themselves and on the coaching staff.  

I do not claim that the Duke coaching staff looked at the data and used the difference in mean as a method for motivation.  What I am saying is that if you are a coach and you are considering whether data analysis and analytics will benefit you in any way, understanding how you can present data to your players does provide an option to make them believe in themselves and unite around an idea as long as you know what the truth is.  In this case, presenting the mean and the variance is for the players.  The median is for the coaching staff.  The players have to believe in their ability.  The coaching staff needs to develop a practice plan to tackle weaknesses and enhance strengths.  The drills and the allocation of time to a problem should address the truth.  A failure in coaching and in data analysis is if the coaching staff believes that the shooting is more efficient and builds a practice plan and strategy on that lie.  

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MEDIAN ILLUMINATES THE TRUTH FOR COACHES

Figures 4 and 5 show a negligible improvement in effective field goal percentage.  The difference in the median is not negligible. 

Efg% below 50% is evidence of a team that struggles to shoot the basketball.  In order to place context we have to differentiate how pre-conference games deviate from conference games.  The one major difference is the quality of opponents.  All high major teams schedule a good number of mid to low major games in the non conference section of the schedule.  The quality of opponents is less competitive in non-conference than conference.  The second major difference is the familiarity conference opponents have with each other versus the unfamiliarity non-conference opponents have.  Duke plays conference opponents multiple times.  Conference opponents have more tape of each other and they have the experience and film of having played each other.  Playing a conference opponent a second time is more difficult.  

These are some of the reasons why teams see a decline in statistics during conference games but despite the context and reasoning, Duke has to shoot the ball better.  The quality of talent Duke attracts gives them an advantage over the majority of ACC teams.  

In order to improve offensive efficiency in 2023, Duke has to be more efficient in their shooting.  In 2022, Duke emphasized getting the ball to the basket. Filipowski’s return means that there will be a similar emphasis on offense this upcoming season.  Teams will look to gap and pack the lane to keep Duke from getting to the rim and in order to loosen the defense and force it to expand, Duke has to shoot better from the perimeter in 2023.  This is why there is an emphasis on effective field goal percentage in this analysis. Effective field goal percentage takes into consideration the higher value of a three point shot.  Consistently making three point shots creates better offensive spacing.

Duke’s decreased efficiency in shooting also fed into Tennessee’s game plan and style of play. If a team can not spread out an opponent, it becomes easier for the opponent to be physical because of the lack of spacing.  Extending out to make contact and to be physical puts the defender on an island with the referees eyes on them.  There is no crowd blocking the referee’s point of view and referees are more likely to call fouls in the perimeter if there is nothing hindering their view.  

Forcing teams to extend out allows Filipowski to play on an island in the paint.  Teams can not collapse and reach, bump, push or throw elbows.      

Duke made 8 more three point shots during conference games than in non-conference games.  The shooting mean was similar which means that Duke took more three point shots in the conference season than it did in November and December.  

Shooting more threes at a less efficient rate is problematic in the postseason. Theoretically, a mid seed will have a more difficult path in the tournament than a high seed.  If you are shooting more threes at a less efficient rate and then face a tough minded defensive team in the postseason, your shooting percentage is likely to take a dip.  It is also likely that your ability to take uncontested three point shots decreases and if you develop a higher dependence on the three point makes, not being able to get a shot off will cause frustration and panic.  Frustration and panic lead to taking bad three point shots which are no different than turning the ball over.  Teams play harder in the postseason than at any other point of the season.  This is a point that I try to hammer when I write about basketball and how the schedule changes from month to month.  

Becoming more efficient and improving three point percentage is key for Duke in 2023.  Being able to open up the floor will make guarding Filipowski a nightmare for opposing coaches and will allow Duke guards and Mark Mitchell to put pressure on the defense with the dribble. The spacing makes it easier to cut to the basket and an expanded defense opens up passing lanes.    

COMPARING OFFENSE AND DEFENSE WITH 2021  

Duke has to improve by limiting turnovers in 2023.  The 2022-2023 team averaged 11.68 turnovers a game.  Averaging less than 12 turnovers a game is what good teams do. Great teams average less than 10 turnovers a game.  A reason why the 2021 team had a better offensive rating is that they did not turn the ball over like the 2022 team. The goal for 2023 is improvement over 2022 and for that to happen, Duke has to become a great team in 2023.  Turnovers is the key statistic and the goal should be less than 10 turnovers a game.  

Advanced shooting metrics favor the 2021 team.  Combine the higher shooting with less turnovers and we can see why John Scheyer’s team took a dive in net rating.  

Duke brings in two freshman guards into the 2023 season but the onus and the pressure to make shots should not be on them. Duke’s freshman guards should have time to adjust to division 1 basketball and the scoring responsibilities should fall on Filipowski, Roach, Proctor and Mitchell.  

Jared McCain should not be bottled up and restricted by Scheyer but he also should not be put in a position where he is forcing a play.  Proctor and Roach give Scheyer the luxury to put the freshman guards in positions for success and to not have games where they are turnover prone.  This is why averaging less than 10 turnovers a game should be a goal for Duke in 2023.  Duke has experienced guards and if Scheyer needs to, he can put the ball in their hands.  

The difference in defensive rating between the 2021 and 2022 teams is razor thin.  Figure 9 highlights a few of the areas in which the 2022-2023 team outperformed the 2021-2022 squad.  

The 2022 team averaged more blocks, allowed less total rebounds and less three point makes per game.  

Dereck Lively’s departure will challenge Duke’s ability  to maintain the edge in rebounding and block shots.  Lively had 82 block shots in the 2022-2023 season.  He was a member of the ACC All-Defensive team.  Lively challenged shots and cleaned the glass.  

Replacing Lively’s production and size on the defensive end will not be easy. Duke does not bring in a 7 footer in this class but it does have two talented forwards.  Duke should benefit on the defensive end from the returning talent.  Last season’s freshmen should be familiar with Duke defensive concepts. Perimeter defensive play will be key to protecting the paint and decreasing Duke’s defensive rating from 2021-2022.  

Filipowski led the team in rebounding and his offensive game should improve as should his defensive productivity.  Filipowski had 16 double doubles in 2022 but the question will be what happens when he goes to the bench?

Roach is a proven commodity and he should be steady as a senior wing.  Duke’s success is dependent on the evolution and improvement of Mark Mitchell and Tyrese Proctor.  

It is said that a college player’s most important time is the summer between their freshman and sophomore year.  Those summer months mark the highest level of growth.  Filipowski and Mitchel were 5 star freshman and Proctor was rated a 4 star by 247.  Filipowski and Proctor were both members of the ACC freshman team and met and exceeded expectations.  

The fate of the Duke Blue Devils rests on its sophomores, especially Mark Mitchell.  Mitchell has the size and athleticism to rise to another level.  He has the ability to take on the toughest defensive matchups and set the defensive intensity.  Mitchell is the X-factor for Duke.  If he is able to raise his game to all-american status, Duke should win the ACC conference and be a national championship contender.

Duke’s success in 2023-2024 is dependent on Scheyer’s ability to weave the pieces together.  To measure Scheyer’s coaching chops and player development abilities, the 2023-2024 Duke Blue Devils should increase their offensive rating, shooting efficiency, decrease turnover averages and maintain or improve their defensive rating.  If Duke’s net rating is one of the highest over the last ten years, Duke should make a deep run into the NCAA tournament and be a title contender. 

Duke has to remember what Tennessee did to them.  A more physical and tough defensive team should not be brutalized in 2023.   Duke has to improve its mental and physical toughness to reach the level of success that it is used to be under Coach K.