College Basketball Advanced Stats Overview: ‘Four Factors’ Formulas and Meanings

Prior to the season, I wrote a number of posts centered around advanced metrics and tempo-free stats, but with more college basketball writers and analysts starting to use them, it seemed like a good idea to provide a brief summary of the key stats and how they are calculated.

Pace and Points Per Possession (PPP)

The purpose behind looking at scoring on a per-possession basis is that it normalizes teams who play at a variety of different tempos.

For instance, VMI ranks third in the nation at 83.1 points per game, but they play at one of the fastest paces in the country and don’t shoot the ball very well.  And just because Wisconsin is 252nd overall in scoring doesn’t mean they are inherently terrible offensively.  Ultimately it boils down to a quantity versus quality proposition.

bo-ryan-wisconsin-college-basketball-advanced-stats-four-factors-formulasThe first piece of the calculation is to arrive at the number of possessions in the game, which is defined as:

Field Goal Attempts – Offensive Rebounds + Turnovers + 0.475 * Free Throw Attempts

A more detailed description of why this makes sense can be found at the old Big Ten Wonk site.

Once you have that, you can easily divide the points scored in the game by that number of possessions.  For a point of reference, here are some numbers through Friday’s games:

  • National Average: 68.5 possessions per game
  • Fastest Pace: Houston Baptist at 75.4 possessions per game
  • Slowest Pace: Wisconsin at 58.9 possessions per game
  • Average Points Per Possession: 1.01 ppp
  • Most Efficient Offense: Missouri – 1.19 ppp
  • Least Efficient Offense: Grambling – 0.78 ppp
  • Most Efficient Defense: Ohio State – 0.84 ppp
  • Least Efficient Defense: Nebraska Omaha – 1.18 ppp

The Four Factors

The other most commonly cited statistics are the “Four Factors,” which statistical pioneer Dean Oliver broke down in his book, Basketball on Paper.  In simplest terms, these are the four factors he deemed most critical to on-court success.

1. Effective Field Goal Percentage (eFG%)

eFG% is calculated by:

(0.5 * Three-Pointers Made + Field Goals Made) / Field Goal Attempts

As you can see, the calculation is virtually the same as a standard field goal percentage, except that it gives additional credit for made three-pointers.  The calculation accounts for the fact that a made three is worth 50 percent more than a made two.  Big Ten Wonk says that eFG% “is roughly analogous to calculating a batting average using plate appearances instead of official at-bats.”

Through Thursday’s games, here are some key eFG% numbers to know:

  • National Average: 49.0%
  • Best on Offense: Creighton – 58.5%
  • Worst on Offense: Grambling – 38.1%
  • Best on Defense: Wisconsin – 39.9%
  • Worst on Defense: Longwood – 57.8%

2. Turnover Rate (TO%)

The calculation for TO% is a simple one:

Turnovers / Possessions

Again, this normalizes the fact that two teams might each turn the ball over 15 times, but the impact of that is greater for a team that has just 60 possessions versus one that has 75.

Here are the numbers to know about TO% this season:

  • National Average: 20.6%
  • Best on Offense: Purdue – 13.8%
  • Worst on Offense: Towson – 30.6%
  • Best on Defense: Ohio State – 27.4%
  • Worst on Defense: William & Mary – 14.8%

To put the Towson one in perspective, no one else is even over 26.4% for the year.

3. Offensive Rebounding Percentage (OReb%)

The calculation for OReb% is as follows:

Offensive Rebounds / (Offensive Rebounds + Opponent Defensive Rebounds)

Instead of looking solely at the raw number of offensive rebounds a team gets, this reduces it to a rate by comparing to the number of missed shots.  Again, as Big Ten Wonk put it, “Rebounds are like hits—and missed shots are like at-bats.”  From an efficiency standpoint, the theory is that offensive rebounds essentially extend possessions and provide additional scoring opportunities.

Here’s a look at how OReb% has played out this year:

  • National Average: 32.3%
  • Best on Offense: Pittsburgh – 43.6%
  • Worst on Offense: Hartford – 21.9%
  • Best on Defense: Bucknell – 23.1%
  • Worst on Defense: Alcorn State – 40.3%

4. Free Throw Rate (FTR)

Again, the calculation for FTR is a relatively simple one:

Free Throws Attempted / Field Goal Attempts

Ken Pomeroy says this metric “measures a player’s ability to get to the line relative to how often he attempts to score.”  In short, it’s a measure of aggressiveness.  Guys who are content to shoot jumpers and won’t attack the basket will end up with a low FTR, while others can provide increased value by making a concerted effort to get to the stripe.

Here are some key data points for FTR this season:

  • National average: 36.5
  • Best on Offense: New Mexico State – 55.3
  • Worst on Offense: Troy – 23.6
  • Best on Defense: North Carolina – 20.4
  • Worst on Defense: Eastern Washington – 64.6

Some of these are pretty extreme.  For example, New Mexico State is the only team over 50.3, and for Eastern Washington, no one else is over 55.6.

So as you look forward to filling out your March Madness 2012 bracket when it comes out, efficiency numbers can provide a different point of view on many of the matchups, particularly as you’re comparing teams from a wide range of leagues with a variety of styles.  Sites like KenPom.com and Statsheet.com provide this data if you’d like to get more in depth.

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Follow me on Twitter (@andybottoms) for more thoughts on college hoops, and check out the latest edition of the Bottoms Line podcast.



About Andy Bottoms

While Andy was born and raised in Indiana, he would like to point out that he grew up shooting hoops in his driveway and not against the side of a barn like you see in all the March Madness promos or in the middle of a field like Jimmy Chitwood. Andy ranks among the top bracketologists according to the Bracket Matrix and has provided his projections to Fox Sports for the past three seasons. When not compiling excuses for missing work during the NCAA Tournament, Andy enjoys spending time with his wife and two daughters. He is a proud IU graduate and co-hosts The Assembly Call postgame show following every IU game. Twitter: @AndyBottoms

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