How to Read Numbers Recaps - Individual Stats

In Part One of "How to Read Numbers Recaps", we looked the breakdown of the team-based stats. After all, basketball is primarily a team game. However, there is obviously a view of how well individual players contribute to the team's success. We attempt to capture this view through the individual ratings.

Below is the basic table that we look at after every game. It may seem busy, because even the walk-ons played, but there is a lot of information contained within this table. For this example, we are going to use the game against Florida Gulf Coast (3/4/08).


What do all of these categories mean, anyways?

Minutes - Self-explanatory

Usage - Usage is the percentage of total possessions that a player consumes. If the game has 67 possessions, how many of those 67 possessions does each player use? Typically, usage shouldn't be any higher than 20-25%. The general idea is that the higher a player's usage, the less efficient they become. It's rare that someone can combine a high usage with a high offensive rating, and these types of players are superstars (like Michael Jordan).

Offensive Rating (ORtg) - Offensive Rating is based on several elements. A player's offensive rating revolves around their role in the offense, how important assists are to their efforts, and how well they do at scoring field goals. On a per-game view, Offensive Ratings should always be compared against the team Offensive Efficiency. If the player has a higher score than the team Offensive Efficiency, then they boosted the average. If the player has a lower score than the team, then that player was a drag on the offense. This higher the offensive rating, the better that player did.

Individual Points Produced - Consider the following scenario: Dominic James makes an assist to Ousmane Barro, who then scores. The team gets two points, but both DJ and Barro should get some credit for producing the two points. After all, Barro doesn't score unless DJ gets him the assist. How does one divide up the credit for the two points? What about the role of offensive rebounds in producing points? Individual points produced attempts to answer these types of questions. Players who get offensive rebounds or give lots of assists get more credit for producing points. Players who receive lots of assists get docked on producing points.

Defensive Rating (DRtg) - Defensive rating is somewhat limited in its capability, and is best used as an approximation. After all, box scores do not presently show any statistics for scenarios where a player is guarded and then misses or makes a shot. Therefore, what is done is to baseline defensive stats off of the team Defensive Efficiency, because the team plays defense. Then, individual player stats are used to adjust individual defensive rating. A player gets credit for defensive statistics like steals, blocks, or defensive rebounds, or they get dinged for committing fouls or not collecting defensive statistics. The lower the defensive rating, the larger the impact that player had on the game.

Net Points Added - In the Florida Gulf Coast game, Marquette ended up winning by a margin of thirty points. Which players had the greatest impact on that win margin? The answer is found in Net Points Added. In every Individual numbers recap, the players are sorted based on net points added from highest to lowest. If a player is positive net points, that player had a positive impact on the game. If a player is negative net points, that player had a negative impact on the game. For the most accurate view, this should always be viewed in the context of Net Points and Individual Points Produced.

Final Note - The total points produced and the total net points added will not always add up to the actual final tally of points and win margin. That's because basketball is a team game and the "team" has to get credit for some of these results too.

Let's look at some examples...

Example - Good production (Lazar Hayward)

In the game, Lazar had box score statistics of 18 points on 6-12 shooting (3-5 from three, 3-6 on FT). He had 11 rebounds (3 offensive), one foul, one turnover, and two steals.

• Lazar had a usage of about 18%, which is around one-fifth of all possessions in the game
• His offensive rating of 116.3 was better than the team average
• Despite scoring 18 points, Lazar only gets credit for producing 13.8 points
• Lazar's defensive rating was much better than the team's defensive efficiency, largely thanks to his eight defensive rebounds
• Out of the 13.8 points produced, Lazar's net impact on the game was 10.4 points of win margin
  

Example - Poor production (David Cubillan)

I'm not picking on Cubillan... he just had the lowest net points score from this game. In the game, David had zero points on 0-1 shooting (0-1 from three), with one assist, one turnover, and one steal.

• David had a very limited usage in the game at less than 3%
• His offensive rating was much worse than the team average
• Despite not scoring, he gets 0.6 points credit from his assist
• David's defensive rating was also worse than the team average
• His net impact on the game was negative 1.8 points. This means that the other players on the team had to contribute more in order to overcome this negative impact

That's the view for how we determine individual player ratings. Most of our detailed graphs and charts on players reference a player's trends on ORtg, DRtg, and Net Points. We'll go ahead and place these articles on the front page so that they can also be referenced in the future. Now, let's get ready for the next game.

How to Read Numbers Recaps - Team Stats

We're going to do something a little different today. The purpose of this article, besides just a recap on Florida Gulf Coast, is to give an overview of the various stats we use and what they mean. In other words, how does one read the numbers recaps? We'll do the review in two parts, team and individual. This is the team overview.

Background on Basketball Statistics

The Four Factors come from the work done by Dean Oliver, whose book "Basketball on Paper" is like Moneyball for basketball. A lot of the work done by Ken Pomeroy is based on the fundamentals of Dean Oliver. All of the analysis that we do is based on his book as well.

The basic premise is that there are Four Factors that dictate how well a team does. The principles are Field Goal Percentage, Turnovers, Offensive Rebounds, and Free Throws. These are all fundamentals of basketball. However, the key difference for the Four Factors is that they've been modified to reflect possession-based statistics. In other words, a team that plays an extremely slow pace (Georgetown - 62 possessions / game) can now be compared to a team that plays at an extremely fast pace (Tennessee - 72 possessions / game). The team's points per game are not comparable, but their points per possession may be comparable.

What's a possession anyways?

A possession is anything that ends the action on the offensive end of the court. Any field goal attempt, any turnover, or even a Free Throw Attempt is a possession. Offensive rebounds negate possessions (because the player extends action on the offensive end of the court). The simplified equation to calculate possessions is FGA-OR+TO+0.475xFTA. Pretty basic, right?

Four Factor Review (Example - Florida Gulf Coast Game 3/4/08)


Offensive and Defensive Efficiency

The first thing to start with is the Efficiency review. Whichever team wins the Efficiency battle wins the game 100% of the time. Efficiency is as simple as how many points a team scores per 100 possessions. Another format of this is just points / possessions.

Against Florida Gulf Coast, we scored 67 points in just around 66 possessions. That works out to 1.01 points / possession, or an Offensive Efficiency of 100.9. Typically, an Offensive Efficiency of 100 is average, and an Offensive Efficiency above 110 is considered good. Therefore, our offensive output was around average.

Florida Gulf Coast scored only 37 points in 64 possessions, which is 0.58 points per possession, or an MU Defensive Efficiency of 58. Obviously, the lower a team's Defensive Efficiency, the better it did. I usually consider 90 to be the threshold for a poor efficiency outing, so FGC did not do very well at all, thanks to Marquette's defense.

Rating Teams and Tracking Trends

Pomeroy rates all of the teams on the basis of Efficiency Margin. This is simply the difference between Offensive Efficiency and Defensive Efficiency. In this game, our Efficiency Margin was 42.9 because the game was a blowout. In games that are fairly close, the Efficiency Margin is obviously close as well.

At Cracked Sidewalks, we track a moving average of Marquette's efficiencies to provide a view of how well the team is playing throughout the season. One always wants to see trends of Marquette's offensive efficiency sloping up, and of Marquette's defensive efficiency sloping down. In addition, by looking at the Efficiency breakdown following a game, one can tell if it was a game decided on the offensive end of the court (both teams with efficiencies above 100) or the defensive end (both teams with efficiencies less than 100).

The Four Factors

effective Field Goal Percentage (eFG%) - This is the same as regular Field Goal Percentage, but it takes into consideration the extra value of a three point basket. The example I always use is that a team gets the same amount of points (12) if they shoot 4/12 from three as if they shot 6/12 from inside the arc. eFG% adds in the extra value.

This is the most important of the four factors and it plays the greatest role in determining which team wins. I usually look above 55% as a good outing, and below 45% as a poor outing. Against, Florida Gulf Coast, Marquette won the effective Field Goal battle at 52.1%. Our game FG% was 45.8%. The formula for this calculation is (FGM + 0.5*3PM) / FGA.

Turnover Rate (TO Rate) - Turnover Rate is turnovers / possessions. A turnover rate of 20% is considered average. Less than 20% is considered good, and higher than 20% is considered bad. Against Marquette, Florida Gulf Coast turned the ball over 39% of the time, or one out of every two-three possessions. Marquette also did a poor job protecting the ball in this game.

Offensive Rebounding Percentage (OR%) - This is a little more sophisticated than just looking at total rebounds or a comparison of offensive rebounds between teams. The basic idea is that every defensive rebound is a potential offensive rebound (and vice versa). Consider for example:

• Team A misses forty shots, and grabs 15 offensive rebounds. This means that the opponent secured 25 defensive rebounds. OR% for Team A is 37.5% = 15 / (15 +25)
  
• Team B misses thirty shots, and grabs 15 offensive rebounds. This means that the opponent secures 15 defensive rebounds. OR% for Team B is 50% = 15 / (15 + 15)
  

In each situation, the team pulled down 15 offensive rebounds. However, the offensive rebounding percentage is completely different. Team B dominated the Offensive Rebounding Percentage by obtaining half of all possible rebounds.

Against FGC, we had 10 offensive rebounds and they had 17 defensive rebounds. Our OR% was 37.0% = 10 / (10 + 17). Florida Gulf Coast had 13 offensive rebounds and we had 23 defensive rebounds. FGC's OR% was 36.1% = 13 / (13 + 23). Even though Florida Gulf Coast had more offensive rebounds, we did better at offensive rebounding percentage (marginally).

Free Throw Rate (FTR) - There are a couple different ways of looking at Free Throw Rate. For consistency, the equation is Free Throw Attempts / Field Goal Attempts. In other words, what percent of the time did a field goal result in a free throw attempt? Against FGC, we took 24 free throw attempts against 48 field goal attempts. FGC took 10 free throw attempts against 47 field goal attempts.

In our next view, we'll take a look at how to read the individual player ratings through the FGC review.