Tag Archives: statistics

ERA doesn’t equal good/bad pitching


Living a few hours from Safeco field, I hear about Felix Hernandez a lot.  For many years he was the only bright-spot for Mariners fans – until the past few seasons.  Felix is a great pitcher, no doubt, but how great?

If we answer with ERA, we have to consider that there are at least 5 things that affect a pitcher’s ERA (earned run average):

  • the pitch that leaves his hand
  • luck
  • the defense behind the pitcher
  • the ball-park &
  • sequencing.

The pitch that leaves his hand is the ONLY thing the pitcher controls.

Felix has no control:

  • of whether the batter reaches on a bad pitch and sprays it to the opposite field – luck.
  • on whether his left-fielder made a good jump on contact (or whether he has the actual speed to get there before the ball lands) – defense.
  • of which ball-parks he pitches in.  Contractually, Felix can choose to play half his games at Safeco, but the other 50%?  That’s determined by the M’s schedule, not Felix.
  • on the sequencing.  Imagine the following two sequences
    1. Two outs, Felix gives up a single, a single, a home-run and then records the final out.
    2. Two outs, Felix gives up a home-run, a single, a single and then records the final out.

In scenario # 1, Felix’s ERA took a “you gave up 3 earned runs this inning” hit.  In scenario # 2, his ERA was only 1 run for that inning.  Same number & kinds of hits, different sequence.

Despite the opinion that statistics ruin baseball, stats are crucial to understanding it.  As the Nate Silver at 538 says,

the better advanced statistics are all about deepening our understanding of how the game is played.

What makes baseball fun to me – is the statistics.  The games are – by and large – boring.  But the numbers they produce?  Those are fun to play with and analyze.  I realize that’s geekdom-central talking but sorry.

For example, let’s go back to Felix Hernandez.  What if we stopped looking at his ERA and started looking at his FIP (Fielding Independent of Pitching). What this stat looks at is a pitcher’s strikeouts, walks, hit by pitches and home-runs.  It compares those four stats with the league-average of defense behind the pitcher.  So that strips out luck and sequencing.

To see Hernandez’s dominance consider the following from Fan Graphs:

Year       ERA       FIB

2009   2.49      3.09

2010   2.27      3.04

2011   3.47       3.13

2012   3.06       2.84

2013   3.04       2.61

Despite an ERA that fluctuates from 2.5 to 3.5 – depending on the year, Hernandez has gotten better every year as a pitcher.   How do we know?  His FIB. This is a very valuable stat – to him and to Mariners.

A stat like FIB is why I pay attention to baseball.  Whether I watch the games or not.