What Hitting Metrics Correlate Year-to-Year?

From SABR member Bill Petti at Beyond the Box Score on September 1:

It is important to not just know the numbers, but the story behind the numbers. How are they constructed? What are they meant to capture? Some statistics are simply reflections of current performance while others reveal more about a player’s skills or talent outside of a single year. It’s critical that we understand the difference.

One place to start in order to bucket metrics into one of these two categories is the extent to which a metric correlates year over year. If a statistic in year one does not correlate all that well to itself in year two it generally is more descriptive than predictive. 

This is the underlying logic behind pitching metrics like DIPS and FIP. Since ERA has a generally low year-to-year correlation (.38), it was a poor predictor of future performance and true talent.

I think if you ask most people what offensive statistics correlate year-to-year you won’t find many confident answers. In order to help us along the journey I decided to run some correlations for common, and uncommon, batting statistics. For those that live in SQL, these numbers are probably well known. But for most, I think it is helpful to have them posted for reference

Read the full article here: http://www.beyondtheboxscore.com/2011/9/1/2393318/what-hitting-metrics-are-consistent-year-to-year

Originally published: September 2, 2011. Last Updated: September 2, 2011.