538 Post: How Much Do Early-Season MLB Records Matter?

For FiveThirtyEight, I wrote about the meaning of early-season baseball. If we want to predict a team’s final, end-of-season winning percentage, we need to regress their April record back to the mean by 62 percent — so if a team starts with an .800 winning percentage, we’d expect them to finish at .614 (or 99 wins) over the entire season. But that’s pretty simple; there are even more fun predictions you can make using April records if you also know a team’s preseason predicted win total. Take a look at how much a team’s forecast can move depending on how it does early in the season:

Anyway, you can check out the whole story here:

Your MLB Team Just Started Hot (Or Cold). How Much Does That Matter?