PREDICTING DANIEL MURPHY’S BATTING PERFORMANCE FOR 2016. I explained my prediction for the World Series performance of Daniel Murphy here. In that post, I tried to apply some of Philip Tetlock’s principles of forecasting. I pointed out that: “It occurs to me that the rotisserie baseball I have been playing for 35 years is quite similar to answering the questions in Tetlockâ€™s forecasting competitions.” So I am applying the same analysis I made in my prediction for Murphy’s World Series performance to forecasting his performance in 2016.
I will begin with his OPS for the last 28 days of the regular season. It was 0.854. I will then reduce that figure by .05 to give more weight to his career average OPS 0f 0.755 and his OPS for all of 2015 of 0.770. I wind up with the same prediction as I made for the World Series: 0.849. This is in the spirit of giving weight to Murphy’s hot hand at the end of the year. Ordinarily I start with a batter’s OPS for a full season and then make modifications based on various factors. (For example, Murphy is playing in a better ball park for batters this year, and if I were not sticking with my forecast from last October, I might bump up my prediction this year for that reason). My optimistic forecast is based on a belief that Murphy was improving his hitting ability rather late in his career. This is acknowledging a bias. My experience is that I give more weight than most people do to recent performance. Probably that is why I wound up with Murphy on my team in two of the three leagues that I compete in.
Murphy is off to a terrific start. His OPS at the moment is 1,103, third in the majors. Maybe Murphy did make a permanent improvement last September.