A bit more math: Park Factors

Some good response on my bit trying to explain why Trout leads Cabrera in WAR (it’s 7.8 to 7.0 according to Baseball Reference this morning; 8.8 to 7.6 on Fangraphs) but I have to say that quite a lot of what I’ve seen shows a fundamental misunderstanding of Park Factors. I think the Twitter exchange I had with Brilliant Reader Joe more or less captures…