What is a Good ERA to Have in Baseball?

What is an ERA? 

For starters, ERA stands for Earned Run Average. It is a common statistic found in baseball that represents the effectiveness of a pitcher. It is tracked over the course of nine innings, and a number is given to represent the value. The lower the ERA, the stronger the pitcher's performance is. For example, a premier starter in Major League Baseball that gives up two runs in nine innings pitched has a 2.00 ERA. Simple enough, right? Well, not every pitcher lasts nine innings a game (this is very rare), so ERA truly carries over to multiple games. 


What makes an ERA so complex? 

Not all pitchers throw the same amount of pitches, and each has a different role they have to play. For example, a starting pitcher who may be asked to pitch six innings a game and throw 90 pitches will be much different than a reliever pitcher or closer who is asked to play just one or two innings a game. This variance lends towards sample size, and as a result, starting pitchers have more leeway when it comes to ERA because they pitch for longer periods of time before being replaced. Shutdown closers, or ninth-inning gems, are generally expected to hold opponents to very few runs and keep the score intact, thus indicating a lower ERA. 


Likewise, as mentioned above, calculating a player's ERA is simple enough. Take the number of Earned Runs allowed (ER) and divide it by the number of innings pitched (IP) multiplied by 9 (represents the number of innings in a traditional game). But there is more to ERA than just this calculation. Key in on earned runs, and keep in mind that these consist of only runs that are errors of the pitcher, not the defense. When a routine ball is hit to the third baseman and he fails to make the play, it does not go against the pitcher and his stats. So, a pitcher with a lackadaisical effort from their defense will not be penalized via their ERA, though they may be taken out of the game earlier as a result. 


History of the ERA statistic? 

The ERA stat first appeared in 1912 in the National League when it was called Heydler’s statistic, before being adopted by the American League and receiving its name change. Henry Chadwick invented the mark with the hopes of finding a way to determine what makes up a good pitcher, aside from wins and losses. 0.86 is the lowest ERA of all time in a single season, recorded by Tim Keefe in 1880. Of all current pitchers, the lowest full-season ERA was notched by Zack Greinke, who had a 1.66 mark in 2015. Clayton Kershaw holds the lowest career ERA of all active players, at 2.48, good for 41st all-time. 


How to tell which role you fit into? 

This is a question that comes down to team-specific roster construction and the weapons that are surrounding you. Generally, players are slotted into the reliever role after first being called up to the big leagues before they ultimately work their way up to the starting rotation. Relievers consist of closers, setup men, middle relief pitchers, left/right-hand specialists, and long relievers. Some teams opt to bring their newer relievers into the game in situations where the game is already out of hand (they are leading or trailing by a significant amount of runs). However, there are always cases of players finding their rhythm at a specific spot and sticking to it. Or, a player may be more inclined to be a full-time reliever or closer if they are not as durable and find themselves struggling to maintain arm strength and control when they reach a high pitch count. Regardless, a player in today's age must be versatile enough to pitch at whichever inning they are required to. 


Oftentimes a manager will have a solid grasp as to each pitcher's strengths and weaknesses. Pay close attention to the next baseball game on TV to see a manager's decisions when it comes to which pitchers to use for which situations. Don’t be surprised if a pitcher is brought in to face just one or two batters and get a key out. This backs up the previous message on a pitcher's longevity and sample size. That same player brought in will be significantly hurt or helped by the outcome of these two batters as opposed to one with half a game or more. This could also lead a pitcher to bring out their best stuff, similar to a runner competing in a sprint versus one competing in a long distance. A manager may ask the reliever (the sprinter) to toss out their fastest and filthiest stuff with more on the line and knowing that they will have a few days to rest. Relievers also generally enter the games with one or two outs already recorded. This helps their chances of getting out of the inning unharmed. In any case, these players are expected to have lower ERAs than rotational pitchers (starters). 


What makes the ERA stat more effective than others? 

The ERA statistic is a tell-tale sign of a pitcher's performance. At the core of baseball record books is one key number. Runs. It’s how every team finds a way to win and is the most important factor when it comes to overall team performance. Ever see the movie Moneyball? ERA, unlike other pitching sabermetrics such as WHIP (walks plus hits per innings pitched), K/9 (strikes through nine innings pitched), or W/L (wins to losses ratio), accounts for runs specifically. Specifically comparing ERA to the W/L stats, a player can have a strong record yet an awful ERA. It all comes down to a team they are surrounded by. 


What does the ERA stat not account for? 

Well, have you ever heard of a hitters ballpark? Take Coors Field for example, known to provide an advantage to hitters with altitude carrying balls out of the park frequently. It is important for us as baseball fans to be cognizant of the fact that it may not be fair to compare the ERA of a Colorado Rockies pitcher, who plays half of its games at home, to a player in a ballpark known to be harder to hit off of. Petco Park, home of the Padres, has proven to be one of the most difficult places for hitters to rake. Also, take into account that some teams may have superstars across the diamond that save runs for a pitcher, therefore keeping their ERAs lower than another. Previously discussed was the earned runs as opposed to unearned runs to account for defensive errors, but how about defensive gems? 


The FIP (Fielding Independent Pitching) fully removes all these defensive problems that factor into calculating an ERA. The four calculations that FIP cares about are primarily on the pitchers with home runs, walks, hit by pitches, and strikeouts. No longer does the baseball world have to worry about Nolan Arenado’s daunting defense, or the strong outfield arm of Ichiro Suzuki, altering their pitchers' ERA. No need for fans to stop their applause or standing ovations- sorry Colorado Rockies fans. Nolan Arenado will be missed. One issue with FIP calculations: they don’t take into account fly balls or ground-outs. Some pitchers are less reliant on strikeouts and more dependent on a strong defense behind them. These guys will likely have a much better ERA than they will FIP. 


Adjusted ERA+

Adjusted ERA+ is a statistic that accounts for ERA while factoring in the pitcher's ballpark and the average ERA of the league of the particular league a pitcher plays in. It eliminates all bias that comes with playing at a particular place or on a particular team and levels the playing field. While the mark has a complex calculation (take the league ERA with park factors adjusted in, multiply times 100, and divide by individual player ERA), it is easy to determine whether a pitcher exceeds or is below average. The average adjusted ERA+ is 100- anything above means a player is performing above average and vice versa. 


So, what is a good ERA? 

There really is no one number that depicts a good ERA as each league has varying trends. One year may be more advantageous for pitchers than others, same with a hitter. However, there is a baseline to expect, depending on the type of pitcher. The total average ERA in 2020 was 4.44 but has already digressed to 4.16 in 2021. When baseball statistics were first calculated in 1901, relief pitchers had a significantly higher average ERA than starting pitchers. The trend reversed in a big way towards the end of the 1900s, but within the last few years, it was nearly identical. In the 2020 season, starting pitchers had an average ERA of 4.46, and relief pitchers had an average of 4.44. 


With that being said, to succeed at a high level in baseball, pitchers should look to maintain an ERA below 4.00. Expect anything below 3.00 to be honored with a promotion (hit 2.00 and you’re likely the cream of the crop) and anything above 6.00 to result in a demotion.