9781422285237 - Analytics: Sports Stats & More

Before analytics, managers went with their gut when making decisions about pitching changes. Today, they have a mountain of numbers at their fingertips to help them make the right call.

“So if you are a general manager [GM] and you want to look at a pitcher, you want to know how that pitcher would perform on your staff, with your relievers, and with your defense behind you. A thirty percent swing of ERA is huge, and having more accurate information will help you make a better decision. It is what I called the ‘Expected ERA’ because it gives the GM a better understanding—and it also gives the fans a better understanding—of what is actually happening.”

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