Defensive Statistics

The methodology listed as "The Fans" in the above table is derived from The Fans' Scouting Reports, as organized by noted sabermetrician Tom Tango. The principle is to collaborate the opinions of informed fans on the often tricky matter of evaluating defense. You can read more about the system and how you can contribute here.
But does a purely subjective system have a role in evaluating team (and individual) defense? It absolutely does as the results on these surveys have been proven to correlate quite well with the best publicly available defensive metrics. Justin Inaz did the legwork and I encourage you to read his entire piece on comparing various systems.

Converting from the fans' ratings to runs involve the following procedure:

1. Calculate the average rating for each position. Based on the teams I have analyzed so far, this comes out to: C-41, 1B-46, LF-46, RF-53, 3B-57, 2B-59, SS-62, CF-63.*
2. Subtract a player's rating from the positional average and multiply the difference by the coefficient of 0.7.
   
3. Apply a positional adjustment by multiplying it by the product of 2). The adjustment is based on how many plays the average player at the position is asked to make. This provides runs saved per season (~1440 IP).
4. Adjust for the actual innings played.
   

For players who played multiple positions, I perform the above for each position played. For simplicity and to save time, a player must have played at least 100 innings at one position for me to do the work. For player's with very high or low ratings, I do lower that bar a bit since they may be good or bad enough to make a difference over even less than 100 innings. Obviously, a player must have a fans' scouting report for any calculation to be done. If there's no report, I assume the player's contribution to be zero.

*This figures are based solely on the teams I have done so far, these will change slightly, almost certainly downward, as more teams/players are added.