Originally Posted by

**Wade>Kobe**
This is one of the biggest hangups with SABRmetrics and is the #1 reason that proves -- to me -- that most who get upset with the stat are just ignorant about it. (Not you, you don't seem to be upset).

In any statistical measure which seeks to compare multiple parts (in this case, about 600 different parts), a baseline needs to be set from which everyone can be compared. This is what "Replacement Player" is in WAR. It has nothing to do with any real backup on a team, or anyone's specific team.

All stats that go into calculating WAR, be it offensive, defensive, or baserunning, all compare the player to "league average." League average is an objective, scientific measure. There is no question or doubt as to what "league-average" is.

Therefore, the first step is always calculating a Wins Above Average. If you find the math on either site, you could do the work yourself to find it, and I believe BR even has it as a listed statistic (FG doesn't). Therefore, everyone is graded against the same standard, and therefore if one player is better than another, that means they were better than the standard by a higher margin.

However, if you place league-average as your baseline, you get a value of "0" for a league-average player. However, by default, a league average player is better than about 50% of the league's players.... which means a league average player is quite valuable.

Therefore, in order to express the fact that a league-average player contributes value, a new baseline -- which is lower -- must be set. This is wehre "replacement level player" comes in. This is considered a AAA player who they'd have to call up to replace a major league player. This, then expresses that league-average players are (insert amount) better than replacement level players, and therefore more valuable than below-average players (who still have enough value to be on a major league roster).

For Fangraphs it is very easy to calculate. A league-average player is worth 20 net runs above replacement every 600 plate appearances.

he equation for Runs Above Replacement would be:

RAA + [(20/600)*PA]

So, if a player is worth 50 Runs Above Average after their positional and park adjustments, and had 700 plate appearances, the equation would run as follows:

50 + [(20/600) * 700] = 73.3 Runs Above Replacement

**You would then need to convert runs to wins. Again, this isn't doing anything "subjective", it is basically making the statistic communicate better information. That is, runs are nice, but wins are more telling than runs. How many runs equal a win?**

FanGraphs uses 10 runs per win, while BR has a very complex formula to adjust for the yearly run-scoring environment. Therefore, BR is communicating better information to the fan, while FG is really just making a cleaner number which communicates better information than runs, but not necessarily information translating to wins.

And for anyone who wants to contend that 20 runs per 600 PA is just a "subjective measure", who cares? It doesn't make the statistic itself subjective because, again, we're just creating a baseline to judge everyone off of. If an average level player is worth 23 runs per 600, that doesn't suddenly change the fact that Trout was worth more runs than Cabrera. It may change the total amount a little bit, but not much.

We do it with statistics all the time. We always create baselines to judge players, and they're more subjective with traditional stats than with advanced stats. At least with this research has been done to come up with the 20R/600PA number. With home runs we create arbitrary endpoints like 30, 40, 50, etc.

In this situation, we always -- without fail -- group 39 HR with 30 HR, and not with 40, even though the player was much closer in value via HR to 40 than 30.