Personally, I like the framework behind FRAR, but I dislike Rate2 which is how they calculate how much over/below average a player is defensively. FRAR was developed so it can analyze a player defensively based on box scores that have been around since forever. Other new wave statistics rely on batted ball type and directional vector off the bat. They're also probability based in that respect. They use a lot more relevant data and that's why they're more accurate. The framework of FRAR is based upon the principle that each position has a defensive run value. This difference actually is equivalent if you calculate between offense between two positions or if you calculate it between defensive prowess of a player moving from one to the other. For example, FRAR base value for a SS is 33 runs. For a 3B it's 22. If a +0 SS moves to 3B, statistically they usually become a +11 defensive 3B. So it kind of works. Also, usually the difference between an average SS and 3B over the course of a season is pretty damn close to eight runs. In fact using EqA this season for those positions and the difference is 11 runs. To do this, you have to adjust everything to a neutral environment and then convert it to the park environment you want it in. It's not apples to apples in the future, but it's apples to apples to value created in the past. BP tries to do this, but honestly they fall on their face. They actually assume that a players all-time EqA would be their EqA overall. They then build a line that would equal that production. This is their attempt to remedy this situation, and it's what they use in PECOTA. Honestly, I don't agree with it one bit. Here's a player card for Hafner. http://i47.photobucket.com/albums/f189/kctigers23/Hafner1.gif There are three EqAs on there. The first one under advanced batting statistics is an average player in his league (AL or NL) for that season. The second one is an average player all time. Their attempt to build a line in a neutral context is listed under Translated Batting Statistics. They start building it assuming the eqa all time will still exist. Like I said this is stupid. In the case of Biggio we're looking at the past, value created precisely over an average and replacement player. Historically speaking the value is more important. Biggio would have been hella good anywhere. His strengths arent affected by any park, but he would not have been as valuable in a place where HRs were significantly increased. He would have still been valuable. Hes a 20 HR guy too. When comparing production of two players this is the correct way to do it. In general this way is fine for the future. Most parks are interchangeable. It's only the extremes that matter, the coors, domes, petco etc. Im not sure if they do. If they do, it doesn't matter. If they don't, they don't matter. All of your road stats are going to be produced, on average, at a league average park. It's going to cancel out. Given the limited sample sizes its probably better not to find runs produced over average for a three game set and compare it to an average player. This brings up something. What does a teams winning percentage represent? It represents how often a team would be expected to win against an average team. What does a person's batting average represent? It represents how often a player gets a hit off of a league average pitcher. In general all statistics are already adjusted this way when there's a large sample size. We don't need to do anything. Sure there is. Only its a probability range. Not a given number.