Forecasting 2003

Is there any skill to forecasting?

By Tangotiger

The forecast today is partly sunny, with a chance of showers. Tomorrow will be partly cloudy, with a chance of rainbow. AOL will go up, with a chance to go down.

There's a large group of people who don't have much, if any, use for forecasting systems (baseball, stocks, weather or otherwise). After all, these forecasting systems are based on probabilities and not certainties, so what good are they? These people reason that they could look at the back of a baseball card, look at his age, and make a decent forecast for his upcoming performance.

There's another large group of people who create forecasting systems, because they reason that there are many intricate details that need to be analyzed so that they can reduce the error range in their probability distributions and create useful and accurate forecasts.

Put up or shut up

Every year, the Wall Street Journal polls the major brokerage houses for their "top 10" picks of the year. They compare the annual performance of those picks against the S&P 500 index (i.e., mom & pop investor). About two years ago, I came across their list over a five-year period. Lehman and Smith Barney were the only ones to beat mom & pop. The other 9 brokerages trailed the index.

Throughout the year, we will be comparing the expectation of the systematic forecasters, the back-of-the-card forecasters, and the baseline forecast.

Four systematic forecasters have been kind enough to agree to supply me with the projected OPS or ERA of a selected group of players: Mitchel Lichtman, Ron Shandler, Nate Silver, and Tom Tippett. STATS did not return my request, so I will have to get them with a little more effort.

The baseline forecast is very simple: take a player's last 3 years OPS or ERA. If he was born 1973 or earlier, worsen his OPS by 5% or his ERA by 10%. If he was born 1976 or later, improve his OPS by 5% or his ERA by 10%. The 1974-75 players will keep their 2000-2002 averages.

The back-of-the-card forecasters are the Primer readers. Step right up, and apply whatever process you want. It would help if you do not use the projections of our forecasters.

The selected players

The 32 players were selected as follows:

  1. Select all players with at least 300 PA or 20 GS in each of the last 3 years, excluding any playing time while with Colorado.
  2. Compare their OPS or ERA in 2002 to their 2000/2001 stats, while making a small adjustment for the change in run scoring each year.
  3. Take the 26 hitters and 12 pitchers with the largest deviations.
  4. Remove the 6 hitters and 2 pitchers that are not expected to be at least a semi-regular or fifth starter, based on the Transaction Oracle's opinion.
  5. Add Javier Vasquez and Jeff Cirillo as exemptions to satisfy Dan and me.

Essentially, this is a list of players that should be hard to forecast, because their 2000-2002 performance has been very inconsistent. I introduced the Colorado condition, as well as the playing time condition, because even the back-of-the-card forecasters would agree that some systematic process to handle those players would be required.

In the coming weeks, Dan Werr, Chris Dial, and I will present some commentary on each of the 32 players. Some time in March, you will get the chance to fill in your ballot, with your forecasts. In the meantime, here are the 32 players that you can take a look at, and watch out for.


Year of Birth - Player
1964 - Barry Bonds
1966 - Moises Alou
1967 - Luis Gonzalez
1967 - Marquis Grissom
1968 - Gary Sheffield
1968 - Roberto Alomar
1969 - Jeromy Burnitz
1969 - Jose Hernandez
1969 - Jeff Cirillo
1970 - Jim Thome
1971 - Phil Nevin
1971 - Rich Aurilia
1974 - Sean Casey
1974 - Jeremy Giambi
1975 - J.D. Drew
1975 - Richard Hidalgo
1975 - Torii Hunter
1975 - Jacque Jones
1976 - Pat Burrell
1976 - Adam Kennedy
1976 - Troy Glaus

1964 - Kenny Rogers
1970 - Aaron Sele
1971 - Todd Ritchie
1973 - Chan Ho Park
1973 - Shawn Estes
1974 - Matt Clement
1974 - Jamey Wright
1976 - Freddy Garcia
1976 - Javier Vazquez
1977 - Kip Wells
1977 - Ryan Dempster