Friday, July 31, 2009

Jimmie Johnson and Kasey Kahne Most Correlated Drivers in 2009

Take a look at the driver correlation matrix, based on their finishes after 20 races this year. In all these blogs, you can always click on the pictures to get a larger view.

What sticks out the most? For a quick review, see the little table here - that correlations above 0.50 and below are -.50 are really big. In my article I will focus on anything above .40 and below -.40, so we can look at some extra data points hiding under the surface.

What we find is that Jimmie Johnson and Kasey Kahne have the strongest relationship with each other, more so than any other pair of drivers. They generally perform similarly at each race, either both of them do poorly, or both of them do well.

On the flip side of the spectrum, Clint Bowyer and Joey Logano are the most negatively correlated with each other. When one does well, the other does badly, and vice versa.

What can all this tell us? It may suggest that certain teams are doing a better job than others in getting all their drivers on the same page. Maybe it tells us that certain drivers have a much more similar style than we realized, that they tend to perform well at the same tracks, and perform badly at the same tracks. We see this with Johnson and Kahne in a big way.

And it can tell us which drivers are the opposite of each other, doing well when the other guy does badly. Like we do with Bowyer and Logano. Maybe their styles of driving are not compatible with each other?

Most notably, higher up in the standings, we see former teammates Kurt Busch and Ryan Newman with a high negative -.43 correlation between each other. Maybe they are drivers with such different styles that they couldn't work well together on the same team. Look now how much better they are both doing since they split up as teammates.

Let's see how teammates this season are doing:

Ryan Newman and Tony Stewart have a correlation of 0. that's right, 0.00 - meaning their results are not related to each other. In fact, Tony is more correlated with the Hendrick guys (Gordon, Johnson, Martin) and even Juan Montoya than with Newman.

At Gibbs, Denny Hamlin is positively correlated with Kyle Busch, but negatively correlated with Joey Logano. At 0.08, Kyle Busch and Joey Logano are almost completely uncorrelated with each other.

Childress teammates Bowyer and Burton have a -0.12 correlation with each other, so despite being next to each other in points, they don't tend to perform next to each on the track. Could this be part of the reason they are struggling this year?

Roush's Biffle and Kenseth are somewhat correlated with each other (0.26), but Carl Edwards is less correlated with both of them, especially with Biffle (only 0.05 between Edwards and Biffle).

It will be interesting to see over the rest of the season how these relationships play out. Will people still perform just as similarly or just as differently in the next 16 races?

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