en.wikipedia.org/wiki/Earned_run_average

In baseball statistics, earned run average (ERA) is the mean of earned runs given up by a ... pitchers' defensive errors) are recorded as unearned runs and omitted from ERA calculations. ... Prior to 1900 – and, in fact, for many years afterward – pitchers were routinely expected to pitch a complete game, and their win-loss ...

www.fangraphs.com/library/pitching/xfip

Expected Fielding Independent Pitching (xFIP) is a regressed version of Fielding Independent .... Better with Less: ERA Estimators – Baseball Prospectus.

www.lootmeister.com/mlb/good-bad-era.php

Examples of what constitues both good and bad earned run average for Major League Baseball pitchers. ... MLB Betting: How to Judge a Pitcher's ERA ... A closer might be expected to have a lower ERA, but for the most part, an ERA of 3.00 is ...

www.homerunweb.com/era.html

How to Calculate Earned Run Average (ERA) As the basic statistical measure ... So, for example, a pitcher with a 3.50 ERA is expected to allow three and a half ...

www.insiderbaseball.com/blog/2010/02/fantistics_blog_2202010_expected_era_xera.html

Feb 20, 2010 ... Expected ERA is a term coined by 2 stat researchers (Gill and Reeve), which developed the following mathematical formula ((.575 * H/9 ) + (.94 ...

captaincalculator.com/sports/baseball/era-calculator

Earned Run Average (ERA) is a baseball metric used put a pitcher's number of ... win/loss ratio (primarily because pitchers were expected to pitch a full game).

www.baseballhq.com/glossary-c-k

A hitter's batting average as calculated by multiplying the percentage of balls put in play ... "xERA represents the expected ERA of the pitcher based on a normal ...

m.mlb.com/glossary/advanced-stats/expected-fielding-independent-pitching

Where "FIP constant" puts FIP on the same plane as league-average ERA: ((Fly ... To determine the latter part of the equation, xFIP assumes a pitcher should ...

www.baseball-reference.com/about/war_explained.shtml

We now handle runs-to-wins calculations in an exact rather than an estimated way. With the ... The adjustment for the difference in league starter and reliever ERA has been moved to the calculation of league average rather than the league ...

www.baseball-reference.com/about/war_explained_pitch.shtml

The pitcher's expected runs allowed is then the sum of his opposition's run ... In the current MLB environment, relievers have much lower ERAs than starters.