This is a follow up from on my last post and it is from a suggestion at Baseball Think Factory. You might have to read the previous post to understand this one.
I plugged the values from 1980-89 into the model. There were 115 guys who had their first year on the ballot. The 1990-2009 model (the one without Rose, McGwire and Puckett), predicted 101 of them within .10 of their actual total. So that was 87.8% of them. 89 were predicted to with .05 or 77.4% of them.
In the 1990-2009 group, 88.8% were predicted to within .10 and 74.3% were predicted to within .05. So the 1990-2009 model seems to predict the 1980-1989 results fairly well. The two predictions that are off the most are for Willie McCovey and Willie Stargell. McCovey got 81.4% while the model predicted 38.95, so he got 42.45% more than expected. The difference was even bigger for Stargell. He got 82.4% while the prediction was 23.3. So he got 59.1% more more. But then the next biggest positive differential was Bench who got 96.4% while the prediction said 69.3% for a difference of 27.1%. Then no one else had a positive differential of even 20% (next highest was 17.5%).
The biggest positive differential in the 1990-2009 study was Fisk, who got 35.6% more than expected. Then the next biggest one was about 23%.
Back to the 1980-1989 period, the biggest negative differential belongs to Aaron. The model said he should get 131% but he got "only" 97.8%, for a difference of -32.8%. That is not too much higher than the biggest negative differential from 1990-2009, which belongs to Fred Lynn, of -26.4. Lynn was the only guy to have -20 or bigger (well, bigger in absolute terms among the negative differentials). In the 1980-1989 period, only 2 more guys were -20 or more. I think Aaron's big negative differential is understandable. He scores high on everything or reached almost every milestone. Great world series performer, gold gloves, MVP, 500HR, 3000Hits, 10,000 PAs, etc. All those all-star games. I think some of the voters would give Aaron more than 100% if they could (or the equivalent of more than one vote). I bet most would say that there is alot bigger difference, say, between Aaron and Brooks Robinson, than the 97.8-92=5.8 difference shows. That implies Aaron was only 6.3% better. But I think most people would say it a bigger difference.
The equation for the 1990-2009 period without Rose, McGwire and Puckett was
PCT = -.0165 + .00077*(WSAS/1000) + .04659*(GGAS/1000) + .0475*MVP + .44741*3000HIT + .25953*500HR + .00267*ASSQ10 -.00103*GGSQ7 + .06416*500SB - .0092*(WSIMPSQ50/1000) + .09891*10000PA