When in doubt, simulate
by Ken Pomeroy on Friday, February 24, 2012
I’ve been concerned about the sample size of this week’s work regarding 3P%. We’re only looking at 8-10 games in each half of the conference season. As Kevin Pelton gently reminded me, there are fewer three-point shots than two-point shots and thus there will be more noise in the 3P%. Still, if there is so much noise over 8-10 games that you can’t see a signal, just think about how much noise there is over six games. Consider that when your bracket goes up in flames.
Still, the offensive 3P% scatterplot shown yesterday was troubling. If the defense has no influence on 3P%, why does offensive 3P% show no relationship between the first and second half of conference play? The only solution is to simulate the conference season and see what the three-point percentage scatterplot would look like if team 3P% were truly independent from shot to shot.
But first,…
The 3-point line is a lottery
by Ken Pomeroy on Thursday, February 23, 2012
Continuing the discussion from yesterday, let’s look at more scatterplots! We’ve looked exclusively at defense so far and in order to get a better understanding of how defense works, we need to look at both sides of the ball. Because clearly the offense has some control over what happens on each possession as well.
To get our bearings, let’s look at something that the defense should have more control over compared to the offense - blocked shots. In all of the subsequent pairs of plots, the offensive plot will be on the left and the defensive version will be on the right. Here’s blocked shot percentage:
This makes some sense. Defensive block percentage is a better predictor of the future than offensive block percentage. Basically, a defense’s ability to block shots is greater than the offense’s ability to avoid them. Anthony…
How defense works: an investigation
by Ken Pomeroy on Wednesday, February 22, 2012
[Note: the graphs originally posted Friday were slightly in error. The corrected data has been posted and does not change the conclusions drawn. My apologies for the mistake.]
The data from last Friday’s post has got me wondering about a lot of things and I hope it did the same for you. Mainly, how does defense work?
First, let’s try to noodle through an explanation of why a team would have no skill in affecting its opponents’ 3P%. If you are on offense, how do you decide when to take a three-pointer? Clearly, there’s some standard for launching a shot. No coach goes into a game telling his team, “we’re going to take 15 3-pointers tonight, regardless of what the defense gives us!” Players have a threshold for when to shoot.
On nights where the defense makes pressuring the ball a…
Defense has little control over opponents’ 3P%
by Ken Pomeroy on Friday, February 17, 2012
I took last season’s conference-only data for every team and split it into two halves. Then I compared each team’s opponents’ 3P% between the first half and second half of the conference season. I did the same for opponents’ three-point attempt percentage (their percentage of field-goal attempts that are from three-point range). The following plots of that data should make it clear that opponents’ three-point accuracy is largely out of a team’s control.
Play-by-Play Theater: Longest foul-free streak
by Ken Pomeroy on Thursday, February 16, 2012
In this edition of Play-by-Play Theater, we investigate how long a team can possibly go without committing a foul. Let’s face it, committing fouls can be fun. Just ask Texas Tech! As with eating candy, it’s quite difficult to go long periods without just hammering an opposing player trying to advance the basketball towards the basket.
Last Thursday, New Mexico State did not commit a foul between the 2:25 mark of the first half to the 6:24 mark of the second half, a span of 16:01. Tweeter @wothism thought that might be some sort of record.
Well, our tweeter mistakenly thought the foul-free stretch was longer than it was, but even had it been 18:48 it still would not have cracked the top ten in my play-by-play database.
There have been 16 cases of a team going…
Murray State and variance
by Ken Pomeroy on Tuesday, February 14, 2012
One thing that bugs me about sports coverage is the stories. Not all stories, mind you. If you’re not interested in 1000 words criticizing the coverage of Murray State’s loss to Tennessee State last Thursday, skip what remains here and spend a few moments reading one of the following stories about Butler. There’s this David Woods’ piece about the Bulldogs’ Crishawn Hopkins, and also Pete Thamel’s look at the day-to-day operations of the program. Both are excellent stories worth your time.
It’s the manufactured stories that attempt to explain the often-unexplainable variability in a team’s performance that I take issue with. Some team salvages its season by going on a late winning-streak and the origins of the streak are explained by a players-only meeting or the team captain stepping up and being a leader, or a renewed emphasis on defense,…
Anthony Davis and his not foul-prone ways
by Ken Pomeroy on Friday, February 10, 2012
A frustrating thing about relying on counting stats to assess a player’s value is that it’s impossible to count things that don’t happen. Yes, perhaps you can watch enough of a player to tell if he is good at not doing bad things, but realistically it is tough. How many people watch a player score a basket and say, “that was a really good job at not committing a turnover.” It doesn’t happen.
For this reason, John Wall was considered a viable player of the year candidate two years ago despite a prodigious turnover rate. Likewise, Kendall Marshall was anointed the best point guard in a America before the season despite a turnover problem. And of course both Wall and Marshall are great players, but it does seem like their tendency to commit turnovers went unnoticed.
In case you’ve been locked inside the Biodome lately, Kentucky’s Anthony Davis…
Is tonight a must-win for UNC?
by Ken Pomeroy on Wednesday, February 8, 2012
I tweeted it on Sunday but it’s worth repeating this morning: There’s a strong case that the suddenly offensive-minded Florida State Seminoles are the favorite to get the one-seed for the ACC tournament. FSU is tied with North Carolina at 7-1 in conference play and Duke is a game behind at 6-2 in what is basically a three-team race for regular season honors.
Nobody is going to make the case that Florida State is better than UNC. Well, hold on, I am sure a few people might. FSU did beat the Tar Heels by 33 in their only meeting, after all. But a home win in isolation provides surprisingly little information on the relative strength of the two combatants. And considering the other 20 or so games played by both teams, I’m comfortable stating the UNC is better than…
Play-by-Play Theater: Earliest disqualification
by Ken Pomeroy on Monday, February 6, 2012
Today’s episode of PBPT comes via a suggestion from John Ezekowitz, one of the brains behind the Harvard Sports Analysis Collective. Ezekowitz was at a game in which Brown’s Tyler Ponticelli, fouled out with 13:34 left in the game, which appears to be remarkably early for a DQ. Usually a player in foul trouble, even a reserve, is protected from action with this much time left in the game.
The NCAA keeps tabs on the quickest disqualification, a record I’ve reported on in this space before. The current record holder in that category is San Diego State’s Ben Wardrop who played just 71 seconds before fouling out in a 2004 game against Colorado State. That record isn’t all that special because the aspirants for such a feat are in the game specifically to foul.…
The untrained eye: Gonzaga vs. BYU
by Ken Pomeroy on Friday, February 3, 2012
BYU beat Gonzaga 83-73 in an 82-possession game Thursday night. I was there. This is what I saw.
Saint Mary’s thanks you, Noah Hartsock
BYU forward Noah Hartsock’s 24 and 14 effort helped pin a second loss to Gonzaga’s conference record, and that combined with the Gaels’ surprisingly narrow home win over San Diego Thursday night puts SMC two games clear of Gonzaga for the WCC regular season title. Gonzaga still has a chance to win a share of its 12th consecutive WCC title by beating Saint Mary’s, but they need the Gaels to lose another game somewhere. That’s not impossible, though. (Remember last season?) The chance of getting the top seed is nearly out of the question, though, because Saint Mary’s will hold the tiebreaker by virtue of its sweep of the team that should be the conference’s third-place finisher, BYU. Nonetheless, let’s see how the…