So, I was flipping through the STATS 1997 Baseball Scoreboard and came across a fun article about Barry Bonds on pages 73-75. The question asked was this: “What will the rest of Bonds’ career look like?”
As a reminder, here is what Bonds had done through 1996:
The article then used Bill James’ Brock6 system to project the remainder of Bonds’ career. Here’s a year-by-year look at Brock6′s projections in 1997 versus what Bonds actually did (I’m including only the stats that were provided in the original article):
Looks about right to me. The projection is peering only one year into the future, so most of the inputs are known and we should expect it to be reasonably accurate.
The projection underestimates Bonds’ batting average, but otherwise this is pretty spot on.
Okay, here’s the drop in batting average. This isn’t surprising given Bonds’ age—he’s 34 years old now, so some slippage should be expected. Same with the stolen bases. The projection does nail homers (though Bonds reaches the predicted total in 151 fewer at-bats).
Nice rebound season for Bonds. The power spike in ’99 was legitimate, and his batting average is back to where it was in ’98. Again, stolen bases are declining, which is fine for a guy in his mid-30s.
I love the fact that James nailed the at-bats. The rest of these numbers are pretty far out of whack. Conditions change, and the best forecasting systems may not be able to account for this.
A year after breaking the single-season home-run record, Bonds wins his first NL batting title, at age 37.
The huge disconnect between projection and reality continues.
Bonds wins the second of two career NL batting titles and demolishes the single-season record for walks. He is now 39.
Bonds is hurt.
At age 41, Bonds finally begins his decline phase. This is roughly the season that Brock6 predicted for Bonds in 2002, when Bonds won his first batting title.
The projection has Bonds declining further, while reality has Bonds repeating his ’06 performance.
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If he gets the chance, Bonds will beat this projection.
This is a remarkably accurate career projection. Brock6 nailed the hits, RBI and walks, and it wasn’t too far off on runs scored. It missed badly on homers, stolen bases and batting average.
In hindsight, it probably was a bit much to expect Bonds to continue stealing 20+ bases a year into his late 30s. As for the jump in home runs… I have a theory, but it’s not particularly original. In fact, you’ve probably heard it from every single person on the planet already, so we’ll just leave it at that.