Pollack: Win probabilities after starting the season 1-0

From SABR member Ryan Pollack at Camden Chat on April 2, 2014:

As fans, we often use the first game of the season as a proxy for the rest of the year. After five months of no baseball, the daily wait for news on the rumor mill, the offseason moves, the signings and trades, the releases, the picks and pans, and the tease that is Spring Training, the team’s first game feels like a herald of things to come. If our team wins, we feel elated and like the sky’s the limit. If the team loses, we become depressed and curse ourselves for getting our hopes up.

But just how meaningful is the first game of the season? What does starting 1-0 or 0-1 indicate about how many games the team will win? And does starting 1-0 mean something different from an 0-1 start?

To answer these questions, I used Bayesian analysis along with research into the Orioles‘ past seasons to estimate the probability of hitting the interesting points on the marginal win curve, given that the team had started 1-0. I looked at how the O’s started each of their seasons, noted whether they’d hit certain win thresholds (converting shorter seasons into 162-game ones), and went from there.

Read the full article here: http://www.camdenchat.com/2014/4/2/5568856/orioles-first-game-season-win-probability-bayes

Originally published: April 3, 2014. Last Updated: April 3, 2014.