Understanding Basketball Statistics - Part 1: Four Factors in Notre Dame Wins and Losses

Basketball is a pretty simple game.  Two teams, two baskets - whoever scores more in the allotted time wins.  Any combination of preventing your opponent from scoring and scoring yourself works.  You can play fast or slow; you can play physical or play with finesse - as long as you have 1 more point than the other guy when the buzzer sounds, congratulations.

Dean Oliver wrote a fantastic book, Basketball on Paper.  Oliver took the moneyball approach from baseball, and started looking at how to apply it to basketball.  Since Oliver has a PhD in statistics from North Carolina, I'm inclined to trust his approach.  He took his technical skills in statistical forecasting and combined them with the coaching philosophies of Dean Smith and came up with what he's titled the "Four Factors of Basketball Success."

In Oliver's assessment, you have to do 4 things well to consistently win basketball games, and each of those has a statistical representation:

1. Shoot the ball - eFG% accounts for the value of the 3 point shot in calculating an effective FG%
2. Take care of the ball - Turnovers per possession
3. Grab offensive boards - Offensive rebounding percentage measures how many of your misses do you grab vs. your opponent
4. Get to the line - Free throws made divided by field goals attempted measures both how often you get to the line and how well you shoot when you get there

In his model, Oliver views shooting the ball as about twice as important as turnovers and offensive rebounds.  He views getting to the line is about half as valuable as turnovers and offensive boards.  If you're interested in diving in more, check out this article on Oliver's site.  It is great reading for any basketball junkie.  Of course, doing each of the four factors well is one way to win basketball games, but as we said, there's more than one way to be effective.  Teams can also be successful by limiting their opponents in any of the four factors.

Lucky for us, StatSheet.com gives us a fantastic resource to look in to how Notre Dame has performed agains the four factors this year.  Starting with the 5 losses, let's take a look at Notre Dame's first 7 games in the ACC and how they stack up from a "Four Factors" analysis.  In future posts, we'll look at how ND's season performance stacks up against the top of the ACC and how individual player performances factor in to this statistical analysis.

Notre Dame 70, NC State 77

(recap here)

Here we can see Irish managed a slight shooting advantage vs. the Wolfpack, but it wasn't nearly enough to overcome the turnovers and the massive gap in free throw rate. The Wolfpack scored 25 points on 78% shooting from the line while the Irish scored only 9 on 75% shooting.  Since we're talking statistics here, let's not confuse correlation with causation.  In this case, the FT disparity was driven somewhat by the Irish fouling late in the game.  State made 10 of 12 free throws in the final 2 minutes of that game.  Much like in football, where we know running doesn't make you win, but winning teams run, the same applies here.  The disparity in FT rate was caused by NC State being in the position to get fouled late and delivering on those attempts.  If you're looking for more causation, take a look at the turnover rate.  The Irish committed 11 turnovers on the night to State's 8.  Giving them 3 extra possessions certainly contributed to State being up 4 with 2 minutes to go.

Notre Dame 68, Georgia Tech 74

(recap here)

Here's a great example of the four factors indicating the outcome of a game.  The Irish suffered another cold shooting night on the road, and GT's 5 percentage point advantage in EFG proved critical, despite the Irish handling the ball better and managing to hold their own on the boards.  Once again, the Irish gave up a huge statistical advantage from the line.  Tech was plus-6 in FTM in a five point game, and again four of those came with under 15 seconds to go in the game.  Notre Dame's poor defense let Tech shoot nearly 50% from the floor, and poor offensive execution late in the game forced the Irish to foul, creating the big disparity in FT rate.

Notre Dame 66, Maryland 74

(recap here)

The similarity in the score line hides the dramatic difference in this game.  The Irish actually held an opponent to 45% eFG and managed to shoot over 50% themselves.  Despite the madness of ACC officiating so far, the Irish were even ahead on FT rate in this chart.  Unfortunately, StatSheet.com calculates FT rate as FTA/FGA.  I much prefer FTM/FGA which factors in your shooting percentage from the line.  The rate shown on the chart hides the fact ND only shot 11-20 for 55% from the line for the game, where Maryland was 17-23 for 74%.  ND's true FT rate was 22% and Maryland's 27% using that alternate calculation.  Despite shooting better, the Irish gave up way to many extra possessions to win this game.  Seventeen turnovers and giving up 20 offensive boards doomed the Irish to an 8 point loss, despite a better shooting night.  Defense doesn't end until you've secured the defensive rebound, and it bit the Irish in Maryland.  Sherman and Atkins committed a combined 11 turnovers on the night.  The Irish need more from their senior leaders.

Notre Dame 74, Florida State 76

(recap here)

This was a wild game, with ND trailing for most of the contest, but getting back in it at the end for a thrilling, but disappointing finish.  This game is a perfect demonstration of 2 things:  One, it isn't always about you doing well in a given factor, it is often about preventing your opponent from maximizing that factor.  Two, shooting cures a lot of woes.  You can see that the Irish outperformed the Seminoles in 3 of the four factors.  However, the Irish lead in the offensive rebounding percentage may have had to do with FSU only missing 21 shots the whole night.  There weren't that many offensive boards to be had.  As we covered in the recap, allowing your opponent to shoot a 66% eFG is a recipe for disaster and indicates a poor defensive effort.

Notre Dame 58, Wake Forest 65

As we mentioned in the recap, this game was closer than the final score indicates, and once again, the FT rate indicates the Irish had to foul to attempt to extend the game, and the opponent delivered 6 straight makes from the line. Much like the FSU game, the Irish did a better job handling the ball and cleaned up the defensive boards effectively. Wake rarely crashed their offensive glass, so the Irish were able to create a big disparity in offensive rebounding percentage, but that wasn't nearly enough to make up for another 14 point gap in eFG%.  Cold shooting in the first half drove ND's eFG under 45% and another passive defensive effort allowed wake to get nearly 55% effective shooting.

ACC Victories

Thankfully, Mike Brey's team isn't sitting on a donut right now, so let's see what we can glean from the 2 ACC victories and how they might help in the future

Notre Dame 79, Duke 77

(recap here)

The Irish "signature win" in this difficult season was a triumph over the Blue Devils at home in their ACC opener.  Notre Dame had a great shooting night, and it helped them overcome another rough defensive effort and Rodney Hood's 5-10 performance from behind the 3 point line.  Notre Dame also managed to keep the talented Blue Devils off the offensive glass and led in both rebounding percentage and FT rate.  This win held a ton of promise.  The Irish did an OK job containing Duke and weathering a pretty impressive shooting barrage in the first 3/4 of the game, but thankfully, they found their defense and buckled down late.  The Irish shot the ball well at home, which isn't terribly surprising, but looking at how they shot better gives a strong indication of where things have been going wrong since.  The Irish had 18 assists on their 30 made FG's.  That 60% assist percentage is in line with more successful Mike Brey teams and well below the 50-ish percent we've seen in overall ACC play from Notre Dame.  They shared the ball and moved much better vs. Duke, and it allowed the Irish to shoot a far better percentage.  Individually, Vasturia earned rookie of the week honors in the ACC with his 3-5 performance from behind the line (60% eFG) which the talented freshman has yet to repeat in other ACC games.  The Irish did a lot more draw-and-kick work to get those 3 point looks vs. Duke.  Atkins maestro performance penetrating the ball and finding open men earned him player-of-the-week honors in the ACC.  It would be great to see the senior be that aggressive on penetration and repeat his 11:2 assist to turnover ratio from that victory.

Notre Dame 70, Virginia Tech 63

(recap here)

Notre Dame's other ACC victory also came at home and provides an interesting example on the importance of taking care of the ball.  The Irish were able to turn over a young Hokie team 17 times in the game and were able to take advantage of those 7 extra possessions, despite shooting 7 percentage points worse than the Hokies from the floor.  This is another example of where FT rate as calculated in the chart doesn't tell the whole story, as the Hokies only managed to hit 60% of their FT's and the Irish were +4 in FTM on the game.  The effective FT rate slightly favored Notre Dame 22% to 19% when you take FTM/FGA.  This game featured a bit of a "hidden stat" as the Irish got 10 more FGA's than the Hokies, but some of that was due to the 6 blocks by the Hokies on the night.  Notre Dame recovered a good number of those blocks.

Wrapping it Up

I'm sure you can see some themes developing here.  The Irish are giving up a lot of good shooting nights to opponents and clearly need to tighten their defense to be more successful.  We can also see where the Irish need to limit extra possessions by cleaning up the boards and taking better care of the basketball.  In the next installment, we'll look at those factors in aggregate for the season and see where they stack up vs. other top ACC contenders.