I have been throwing around my projections a lot and not explaining them. That was a bad idea. In this post I will explain how it works and do an example. My example will be Cody Ross
Okay, it has been found that a season's significance in projecting next season is 80% less than the past season for hitters. For example, the most recent season would have a weight of 5, the 2nd most recent season 4, the 3rd most 3.2, so on. Just keep multiplying by 0.8. So let's do WAR since it's a counting stat and you don't have to normalize by PAs. So the sum of Cody Ross's multiplying WAR by PA is 33.8. When you divide that by the total number of the weights, for example, if a player played 3 seasons, 5+4+3.2= 12.2, so when you divide by that for Cody Ross, it's 1.6. Then we need to know this for PAs so we can find WAR/650. Cody Ross using this system, has 421 PAs. His WAR/650 is 2.5. Then we need to apply an aging factor. Cody Ross will be 31 for the 2012 season. Research done by MGL shows that 31 year olds have 88% of their peak value, applying the weights we found earlier by season, we can find that the 2.5 WAR projection was for 93% of his peak,To find Cody Ross's WAR total, divide by .93 then multiply by .88. It's 2.3. Given starter's playing time, we can reasonably expect Cody Ross to put up 2.3 WAR next year, a little more than average.