MLB Skill-Interactive ERA (SIERA) Explained

Nowadays, there are tons of baseball metrics out there, including Skill-Interactive ERA (SIERA). Different abbreviations and acronyms get thrown around by MLB fans and bettors all the time, but what do they actually mean?

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If you want to learn about skill-interactive ERA (SIERA), we’ve got you covered. This statistic can be hugely beneficial when it comes to betting on baseball, so we highly recommend sticking around.

How Does SIERA Work?

SIERA stands for skill-interactive earned run average. Since traditional earned run average (ERA) is not overly useful when it comes to proving the true skill level of a pitcher, SIERA is widely used to gain a greater understanding.

Essentially, SIERA aims to reward the pitcher for what they do well and penalize them for what they do badly. This metric calculates a pitcher’s performance by attempting to eliminate factors they can’t control. Still, SIERA considers balls in play and adjusts for the type of ball in play.

Estimating ERA through walk rate, strikeout rate and ground ball rate, while eliminating the effects of the park, defense and luck, SIERA is a great way to evaluate a pitcher’s ability.

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How to Calculate SIERA

Okay, bear with us on this one. Although the formula for SIERA looks crazy, you can break it down and look at each part of the calculation on its own. According to MLB.com, this is the formula for SIERA:

6.145 – 16.986(SO/PA) + 11.434(BB/PA) – 1.858((GB-FB-PU)/PA) + 7.653((SO/PA)^2) +/-
6.664(((GB-FB-PU)/PA)^2) + 10.130(SO/PA)((GB-FB-PU)/PA) – 5.195(BB/PA)*((GB-FB-PU)/PA)

Don’t worry, there are plenty of online SIERA calculators that can help you figure out the equation. All you need to do is enter the relevant statistics, and you will get the answer you’re looking for.

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How Bettors Can Utilize SIERA

SIERA holds significance in the world of baseball betting because it offers a more comprehensive view of a pitcher’s performance compared to the conventional ERA metric.

Relying solely on ERA might lead to the oversight of a pitcher who is performing well but isn’t achieving the expected results when viewed through the lens of ERA. Accordingly, you can use SIERA to aid your MLB bets.

Since you can use SIERA to identify pitchers who have an ERA that is not truly reflective of their overall effectiveness, bettors can take advantage of skewed odds in multiple markets.

If you can track down these pitchers, you will give yourself a great chance of beating the bookies. From moneylines and totals to props and futures, there are lots of different baseball betting markets where SIERA comes in handy.

It is worth remembering, however, that you should always consider other stats alongside SIERA. While SIERA is a strong metric, taking into account other stats like FIP and wRC+ will only enhance your chances of success.