Thursday, September 21, 2023

Dunk Calculation Reveal in VABG Game - Sample Duke 2015 vs. Nebraska 2014

 This post is more for fellow nerds as I prepare to play my next Value Add Basketball Game - Coach K's last national champions (Duke 2015) vs. Nebraska's only team to make the tournament this century - from the year before Duke's title in 2014.

We originally allowed only one team from each century for each school, but added yet another Duke team when we went through the greatest teams left out so far - though still limiting to just a few teams from each school in our 179 great all time teams. When the 2024 conference realignment was decided we would make sure every team in one of the big five conferences - the Power 5 football plus the basketball-only Big East - and 2014 was the team we chose for Nebraska.

The year before we went through the last couple of tournaments and picked a number of new teams starting with Ja LaMont's 2019 Murray State team. 

Having now added teams in a few waves, we wanted to also go back through and apply the exact same criteria for calculating the Dunk Ranges and defensive equivalent Adj Dunk Range. These are the most important final stat because they adjust for eras of play, and level of competition. Without the dunk range a team with the exact same stats playing SWAC opponents would have the exact same cards as a team with the exact same stats playing in a power conference. The dunk range calibrates very accurately to adjust for how each player would likely do playing against average competition.

We have not detailed how these are calculated until this blog. For starters, this google sheet contains all the calculations that go into the calculations. We are as precise in this as we were in determine that if a team is at home in a game then letting them flip any die result of 36 or 66 for the other would on average adjust to give the home team a 3 point a game advantage in an average game of rolls.

While we are going through the cards using the google sheet above to adjust teams dunk ranges, you can still keep playing with current cards. Only the dunk ranges and adj opp dunk ranges will be adjusted.

To show you the process, we will start with the Duke 2015 cards and calculations.

You go through the top row (starters only). Start with the point guard, Tyus Jones above, and below under "Die 1" you enter 2 for three-pointers made (1-2 range), 4 for two-pointers made (3-6 on his card), 4 for fouled (7-10 on card) then on Offensive Rebounds look at the range at the bottom and he actually has no offensive rebounds so gets a 0. 

Looking further down in the defensive section, you enter 5 for steals (1-5 on card), 1 for blocks (21-21) and 1 for defensive rebounds (1-1). You do this for all 5 positions. Then when you are done, you still need to see who gets the ball on rolls of 6, 7 and 8 and copy just the first four items for the player to the left who gets the ball on those rolls (but do not copy the offensive rebounds over - you can see they are blank below). 

Once all the numbers above the two yellow highlighted rows are entered, you turn your focus to the red number at the top, which are the offensive and defensive Adj (average points per possession the cards should produce when you play the game). 

You look at page 2 of the google doc above to get the target number for the team. The chart showed Duke should produce 1.21 points per trip against average competition, and in fact their dunk range of 51-60 calculated to 10 dunk numbers but that yielded a first red number that was too high. The next is trial and error. We tried lowering each "dunks" number to 9, and when we did that the expected Offensive efficiency did in fact adjust to 1.21. We adjust all the cards in the game for Duke 2015 to a 51-59 dunk range.

Likewise the defensive dunk adjust had been -2 when we first did the Duke cards, but that left their defensive Adj in red below 0.98, so we played with that and 0 is the number that go the number to the target 0.98 for expected points per trip Duke should be expected to give up in the game, so they get a 0 adjustment on defensive, which is just barely average, so weak for the game while the +9 on offense is strong.

Keep in mind that does not mean that a team with a +9 is better than a team with a +4 - it may be a team with a +4 has incredible numbers of 3-pointers made and offensive rebounds etc, and so only needs a slight adjustment on the dunk range to calibrate their offensive to be exactly as good as it should be.

Next we go to their opponent, Nebraska 2014. After all the same steps, Nebraska's dunk range was lowered from a 51-54 dunk range to no dunk range (which we list as 51-50 meaning no numbers to get to their target 0.98 efficiency, which is very weak in the game.

Their adjust dunk opponent range was -1 and that turned out to calculate perfectly to get them to the target 0.98 so no change was made to the card.

Taking all of the above, Duke's offensive dunk range is 51-59, and with Nebraska's -1 makes it 51-58, which actually adjusts in the table in the game shows that is actually a 51-62 in the game. If Duke has the ball and a 51-62 then the player has the option of dunking the ball - which he would take unless the 20-sided die was a 3-pointer made or if it drew a foul on a good player to foul him out of the game perhaps. 

Ironically the Nebraska offense was zero and the Duke defense was also zero, so if anything in the 51-66 dunk range comes up then nothing happens and we ignore and whatever happens on the 20-sided die is the result.

If Duke still had a -2 on their cards and Nebraska had a 0, then the result would be a negative 2, and in that case on the game chart it becomes a 51-52 but that is a STOP range, meaning the player simply misses the shot and the one defending him gets a defensive rebound.

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