Babe Ruth's aging vs. Barry Bonds' aging, Part 3

Click here to read Part 1.

Click here to read Part 2.

I recently read the book Cooperstown Confidential by Zev Chafets. 

On pages 184-185 it has

"Cole and Stigler (two academics) pointed out that Babe Ruth hit 198 homers in the last six years of his twenty-two year career, 28 percent of his career total of dingers. In the last six years of his career, Barry Bonds hit 195, or 26 percent. "There is no convincing way," the study said, "to demonstrate that Bonds' performance owed to drugs more than Ruth's did to his prodigious use of alcohol and tobacco." Which, of course, was nothing."

In this post I will look at how slugging percentage relative to the league average (Rel SLG) changed as both Ruth and Bonds aged. 

The table below shows their Rel SLG for every 4 year period by age, all the way from age 24-39.

Ages	Bonds	Ruth
24-27	1.416	1.931
25-28	1.561	1.980
26-29	1.583	1.914
27-30	1.591	1.749
28-31	1.546	1.777
29-32	1.472	1.783
30-33	1.458	1.763
31-34	1.459	1.796
32-35	1.482	1.797
33-36	1.640	1.743
34-37	1.764	1.735
35-38	1.840	1.690
36-39	1.931	1.577

 

For example, from age 36-39, Bonds had an .809 SLG. The NL SLG over those years was .419. Then 

.809/.419 = 1.931. Bonds' SLG was 93.1% higher than the league average from age 36-39.

It is clear that Bonds had by far his best years late in his career while Ruth had his best early on. Ruth also slowed down quite a bit in his late 30s, the time when Bonds improved.

Would Willie Mays have hit 800 HRs if he had played in a normal park?

That is what a couple of announcers said the other day. The idea is that winds were so strong that Candlestick park cost him alot of HRs.

This issue has come before. Here is a letter I wrote that was printed in the NY Times back in 2010 that explains why this is not likely. See Love and Baseball.

"I certainly enjoyed reading Pete Hamill’s review. But I disagree with him that Candlestick Park and its strong winds cost Mays 100 home runs. Using the Retro­sheet data, I found that from 1960 to 1971, his home home-run percentage was 6.72. In road games, it was 5.8 percent. He played only part of 1972 with the Giants. His home home-run percentage was 15.8 percent better than the road home-run percentage (since 6.72 divided by 5.8 equals 1.158). For the average National League player in this period, the home home-run percentage was 2.34, while on the road it was 2.25. The home home-run percentage is 4 percent higher than the road home-run percentage (since 2.34 divided by 2.25 equals 1.04). Mays seems to have gotten more out of his home park than most players. If we give him 100 more home runs at home (he actually hit 202), his home home-run percentage rises to 10.04. That is about 50 percent better than what it really was."