Sarris: Are baseball’s fundamentals changing?

From SABR member Eno Sarris at FanGraphs on November 12, 2014:

It’s easy to see that baseball has changed over the last couple of decades. Walks, strikeouts, homers, and stolen bases have all seen their ups and downs, and we’re currently experiencing a valley in terms of offense. Games are longer. There’s instant replay.

But there’s evidence that players are getting similarly better and worse at these things — the distribution hasn’t changed, the graph has just been shifted. It’s possible that the relative value of certain events in baseball as a whole could still be about the same. A stolen base’s relationship to a win could be unchanged if the distribution of stolen bases is similar, and there are just fewer of them.

Is that what you find when you look back empirically? If you relate strikeouts, walks, stolen bases, and home runs to winning, is that relationship steady over these turbulent times?

 In order to try and begin answering this question, I broke baseball into four pieces since 1974. I took a glance at this annotated history of offense and tried to pick some obvious groupings, but I wanted them to be roughly similar in size and some randomness was alright. Then, I simply correlated team performance in some key categories to their winning percentage. The “plus” stats below are all indexed to league average since I was asking “Has performance relative to the league in certain factors of the game become more or less important over time?”

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Originally published: November 12, 2014. Last Updated: November 12, 2014.