Theory about Sports ratings systems use a variety of methods for rating teams, but the most prevalent method is called a power rating. The power rating of a team is a calculation of the team’s strength relative to other teams in the same league or division. The basic idea is to maximize the amount of transitive relations in a given data set due to game outcomes. For example, if A defeats B and B defeats C, then one can safely say that A>B>C. Jeff Sagarin’s systems, the NY Times system, and the Dunkel Index, are some good examples. I personal use J.J. Bascus power rating systems. I incorporated his system with my evaluation of my threads in NBA forum and was 5-0 "with" and "against" spread in NBA Championship games[ all my threads posted if you care to check?]
Rating systems can not ignore “throw-away” games. These are games where teams have already earned a post-season bid and have secured their playoff seeding before the end of the regular season, and want to rest/protect their starters by benching them for those remaining regular season games. This usually results in unpredictable outcomes, but without a mechanism to ignore such games (which runs counter to the goals of such systems), this will unintentionally skew the outcomes of rating systems.
Mr.Hårr¥THëHÄT
PS.If you are recreational bettor please disregard this post.