Before I left for Boston I mentioned a post by Climbing the Ladder that published plus/minus data for the previous MLS season. It's a good start, but some of the results just didn't pass the laugh test for me. (I'll explain why much later today.) While I was at the conference, I talked with Joe Sill about his adjusted plus/minus rating in basketball, and I felt that there were enough commonalities between basketball and soccer, especially in the teamwork aspect of both games, to at least look in that direction toward a better solution. His hoopnumbers.com site refers to a couple of publications: this article that references the plus/minus rating developed by Wayne Winston and Jeff Sagarin, and a derivation of the adjusted plus/minus rating by UNC-Greensboro economics professor Dan Rosenbaum.