The building blocks of UofL's offense and defense
What do analytics reveal about the Cardinals' strategies?
The goal of basketball is pretty simple at its core: score more points than the other team. The tactics and strategy that a team uses to get to that goal can be incredibly complex, but I can summarize the basic idea as “either take more shots than your opponent or be better at scoring off of them”. Let me explain that a little more…
Take more shots means…
Commit fewer turnovers than your opponent OR
Rebound your misses more often than your opponent
Be better at scoring off of them means…
Hit a higher percentage of your shots OR
Hit more threes to make up for a lower overall percentage OR
Get to the free throw line more often and hit those
We can quantify how good a team is at either of these areas, and I’ll call these metrics Shot Volume and Shot Making.
Shot Volume
Shot Volume is a concept that college basketball writer/thinker John Gasaway has written about. It’s usually calculated as FGA/(FGA + Turnovers - Offensive Rebounds) x 100. The numerator is scoring chances and the denominator is a crude estimation of possessions. I’ve always preferred shot volume scaled on a “per 100 possessions” basis so that it crucially is not affected by pace of play, but at how effective a team is at turning possession into a chance to score. It’s possible to have a shot volume index above 100 if a team records more offensive rebounds than turnovers. Gasaway’s methodology ignored free throw attempts altogether, which I disagree with. A team who draws a lot of free throws should be increasing their shot volume by doing so; in fact, free throws are more productive than field goal attempts due to the higher percentage at which they’re made. I’ve adjusted the formula as follows:
Including free throw attemopts as scoring chances in the numerator by:
Accounting for the fact that a single free throw “possession” has multiple attempts; the common conversion is 0.475 FTA = 1 possession
Accounting for the higher rate of conversion on FTA; this varies year by year but FT% averages about 1.4x effective FG%
Including FTA in the possession denominator
My adjusted formula is (0.475 x FTA x 1.4 + FGA) / (FGA + 0.475 x FTA +Turnovers - Offensive Rebounds) x 100. Again the numerator is scoring chances and the denominator is possessions.
Shot Making
The whole point of offense is to put the orange ball through the hoop; that’s Shot Making. To better separate offense into volume vs shot making, I came up with a complement to Shot Volume to evaluate how well teams produced given the volume they created. Because the numerator of Shot Volume represents scoring chances, I can come up with an expected points per 100 possessions by multiplying scoring chances by effective field goal percentage. eFG% works because I scaled the volume of free throw attempts to be equivalent to a field goal attempt, and eFG% accounts for the value of three pointers vs two pointers. If I multiply Shot Volume by average eFG%, I get expected points per 100 possessions. I can compare that to a team’s actual points per 100 possessions to calculate how much more or less effective that team was at scoring from their attempts. The formula is:
Expected pts/100 = Shot Volume Index x Average eFG% x 2 points
Actual pts/100 = Pts For / (FGA + 0.475 x FTA + Turnovers - Offensive Rebounds)
Shot Making Index = Exp pts/100 - Act pts/100
Shot Making Index is pretty similar to True Shooting Percentage, although teams who score incredibly well or incredibly poorly from the free throw line will show up a little differently in SMI than TS%.
Breaking these down even further
All shot volume isn’t created equal, of course. Layups go in a lot more often than 18 foot jumpers, and shooting free throws will tend to lead to a lot more points than avoiding them. We can add to our descriptive metrics to get more complete picture of how teams perform on offense; these can also be used to evaluate a team’s defense.
Volume/Shot selection
Shot Volume (explained above)
Rim Pressure Frequency: the % of scoring attempts made up of shots at the rim or free throws (converting 0.475 FGA per 1 FTA); note that “scoring attempts” = all FGA + 0.475* FTA
Midrange Frequency: the % of scoring attempts made up of 2 pointers not at the rim
3 Point Frequency: the % of scoring attempts made up of 3 pointers
Scoring Efficiency
Shot Making (explained above)
Rim Pressure Scoring: the effective field goal percentage on shots at the rim plus free throws (converting 0.475 FGA per 1 FTA)
Midrange Scoring: the field goal percentage on 2 pointers not at the rim
3 Point Scoring: the field goal percentage on 3 pointers
I was able to download team and opponent data from Sports Reference as well as shot location data from Hoop-Math.com. I compiled each metric for each team in the country, and every team is graded on their percentile rank among all teams. For offense, a higher percentile rank means the team generated more shots or shot a higher percentage (even for midrange shots, as distasteful as I personally find them). So, if Louisville is in the 83rd percentile on midrange frequency and 34th percentile in rim pressure frequency that means they took midrange shots more often than most teams and shots at the rim or free throws less often. For defensive ratings the percentiles are flipped, so a higher percentile means fewer shots allowed or a lower shooting percentage. One last note, these stats aren’t adjusted for opponents…so playing tougher opponents will lower them somewhat. Want to dig through the data yourself? I’ve posted it on Google Drive so anyone can check it out: Shot Metrics Data
So, how did Louisville perform in 2022-23?
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