Though the structure of baseball has remained largely unchanged for a century, our examination of the game and its talents is ever-evolving. With the onset of advanced metrics, the most dissected facet has been pitching. Easily the most volatile aspect of the game, pitching tendencies seem to change annually. Most glaring of all is the decreased length a starting pitcher will go into a game since the keeping of such statistics began.

In 1901, at the onset of many popular pitching stats, the average [starting] pitcher threw a complete game in almost 90% of his outings - typically only limited by injuries or isolated incidents causing them to be removed. At the time, it made sense to rate the effectiveness of a pitcher on what they do on a ‘per 9 innings’ basis.

As of 2022, the average starting pitcher (not named Sandy Alcantara) throws all 9 innings less than 1% of the time - with an average outing of just over 5 innings.

Almost no single pitcher will ever throw all nine innings in a single game in their entire career, yet stats rated ‘per 9 innings’ remain the most popular way to examine pitcher performance - over 100 years post-inception. Perhaps the most inappropriate mainstream statistic to gauge pitching talent remains ERA (Earned Run Average). Though the disparity is obvious when applied to starting pitchers, these concepts are especially relevant when applied to relief pitchers.

For example, when one sees a reliever with an Earned Run Average of 2.00, one will assume that reliever is effective; This despite the fact that we all do not expect him to relinquish an “average” of 2 earned runs each appearance. ERA is relatively/effectively accurate, but not conceptually accurate in its representation. Rather, a reliever’s ERA more conceptually represents the totality of his mistakes. Now, whether the ERA signals a trend of repeated mistakes, or infrequently large ones, is a mystery at a glance - yet another knock on ERA’s effectiveness.

Innings Pitched/Total Appearances = Length of average Appearance

I propose not a new statistic to add to the soup, but rather a change in the ERA formula to be rated for volume - per length of Average Appearance. The new change would adjust ERA to “Earned Runs/Average Appearance” rather than “Earned Run Average/9 innings”.

“ERA etc. might not be perfect, but who cares? Is it hurting anyone?”

Aside from providing a visually inaccurate depiction of talent for fans, “per 9 stats” such as ERA have driven pitcher value in the market for as long as they have existed. We have already explored how the current ERA stat is outdated. We have already explored how the ERA stat is unfavorable to relievers and other pitchers that throw fewer innings. As time goes on, we are beginning to realize the negative impact of that in determining a player’s worth - so much so that MLB has proposed using advanced metrics to formulaically determine player salary in light of a heavy reliance on archaic statistics. The integrity of annual player awards, accolades, and Hall of Fame eligibility have all been tarnished, in part, due to the same over-reliance.

“If that’s the case, then what is there to do about it?”

Aside from work done within MLB to improve the understanding of player talent on a league-level, it is just as important to educate fans on how to best understand the players they see and cheer for. As part of a regular segment, we will experiment with the concepts outlined above in an attempt to “re-roll” relief pitcher stats with our new ERA formula. When combined with player-value statistics such as Win Probability Added and Wins Above Replacement, the aim is to establish a more reasonable understanding of RP statistics at a glance.