FanPost

Graph Time with Sax: Efficiency x Usage

From the Fanposts.

As everyone knows, offensive rating (ORtg) is an advanced stat estimating how many points a player produces when they end a team's possession, and %Poss (sometimes "usage") is how many of those possessions a player is responsible for. These two values go together, as obviously a player who is efficient but doesn't touch the ball much probably isn't as good as a player who scores both efficiently and often.

One thing we can do with these two values is make a graph like this, plotting %Poss against ORtg. Here are the KU players from 2013-2015 with 40 %Minutes or more.

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I put descriptive phrases into the corners to help remember which quadrants are which.

There's some things to see here...

The differences these season have been dramatic enough that there aren't too many surprises in this graph. We know Traylor and Selden were seeing big drops in offensive value despite not really being asked to carry much more of the possession load. We knew Mason had made a big leap.

Maybe it wasn't clear that Ellis, despite the drop in his efficiency, is a lot more involved in the offense and actually pretty close to the efficiency/usage of Embiid and Wiggins last year.

But it's still not clear how much things are worth. Travis Releford is sitting pretty up in the assassin's guild, but how does that REALLY compare to Jeff Withey's place on the plot, or Kelly Oubré's?

What's up with that gray line?

Good question! It is a contour of Usage * Efficiency that runs through (130 ORtg, 15 %Poss). So, if player A has a 130 ORtg and 15% Poss, he produces about the same offensive value over 100 team possessions as Player B with a 97.5 ORtg and 20% Poss. That's quite a difference, and a good illustration of why ORtg needs to be paired with %Poss.

If you're on that line, your ORtg * Poss is 19.5.

You can think of that line as a contour line on a topographical map. If you move along that line--or parallel to it--you are staying at pretty much the same altitude. There's nothing special about that one line; lots of lines could be drawn, that's just an arbitrarily chosen one. Instead of constant altitude, the line represents a constant value of "points per team possession".

For example, Naadir Tharpe happens to be right on the line given for his sophomore and junior years. This means that-- even though from 2013 to 2014 he made quite a leap from ORtg, and dropped his usage--he was producing about the same number of points per team possession when he was on the floor. He played more minutes, and he scored more points, and his role changed, but his points per team possession didn't really change.

Releford and Selden are pretty close to that same line, and one way you can think of it is that they all have about the same offensive contribution per 100 team possessions.

Another example is Brannon Greene. He missed the 40% minutes cutoff, but he'd be off the chart with a 131 ORtg and 15.9 %Poss, just above and to the right of Releford. That means over 100 team possessions, Greene has been on average responsible for 15.9 of those possessions, producing (131.2/100 * 15.9 = 20.86) ~21 points of offense. This is just slightly better than Brady Heslip last year (143.6 ORtg, 14.4 %Poss = 20.69 points per 100 team possessions).

But, this is ALSO about the same for Frank Mason (as a frosh), Kevin Young, and Elijah Johnson. You can kind of eyeball and see they might all be on the same contour. Even with that range of efficiency and usage, per 100 team possessions they participated in, all those guys, at those times, were putting up about the same points.

This might be kind of surprising. You might think of EJ, KY, and last year's Frank Mason and not place a very high value on how much difference they made on the scoreboard on the offensive end. But statistically, that's about the same impact Brady Heslip had when he was on the court.

Fun With Points Per Team Possession

So by straight up multiplying ORtg and %Poss we end up with a kind of points per tempo. What can we do with it?

Well, we can look at the PPTP of all the KU players since the 2008 team. Why not? Who is the best KU scorer over this time? What do the scoring profiles of those teams look like with this metric? Form your preconceptions now.

First, PPTP by year:

Keep in mind that 20 points per 100 is sort of the cutoff for Joe Average player. 25 is a good player (e.g. 125 ORtg and 20 %Poss). A PPTP of 15 is pretty bad, for a 20 %Poss player that would be an Ortg of 75. I.e., slightly less efficient than Landen Lucas.

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This is your daily reminder that Conner Teahan played significant minutes on a NC game team.

KU has had some balanced teams (2008, 2010) and some less balanced teams (2011, 2012) over that time. This year's KU team is more balanced at the top, and it's fairly clear also to see that without Mason's scoring this year would look a lot like last year except worse.

Also there is some support for the intuitive idea that it's better to have 5 balanced, efficient scorers than it is to have 2-3 focal point scorers and 2-3 ahem defensive specialists.

Sorted by player:

TRob in 2011 was more of scoring beast than I remember, when he was on the floor.

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There you have it. The 2011 edition of Marcus Morris is the most prolific scorer, by team possession, that KU has had since 2008, and Brady Morningstar worst KU player at getting points onto the board.