EMERA, which is short for Expected MLB Earned Run Average, is the ERA you would expect a given minor league pitcher to run over a full season in his present state if he were immediately called up to the Majors.
Once again, here is an average EMERA for the level each of the four full-season minor league affiliates play at. I used only players who had a minimum of ten innings pitched at a given level to make sure I had a decent sample.
West Tenn: 7.30
High Desert: 12.80
Basically, if you have an EMERA equal to one of the above totals, your performance is equivalent to an average pitcher at that level.
If a pitcher runs an EMERA appearing similar to the ERA of a typical MLB pitcher, this indicates the pitcher in question, based on his performance, could pitch in the Majors right now. Obviously, a lot of other variables are at play and the number is based purely on 2010 pitching performances at the given level. So I'm not about to consider these numbers definitive. But they are a helpful guide to how well the pitchers are doing at their given level.
For pitchers who have pitched at multiple levels, all numbers are based on the level at which the player pitched the most. For example, Steve Bray's number is based on his AA numbers while the handful of innings he threw in AAA are ignored.
I broke the pitchers down by tiers of 12. If you were to completely ignore development schedules and plans, you could slot these pitchers by their given tier: Tier one would be your AAA pitchers, tier two would be AA, tier three High A and tier four low A. That in itself can provide a guide to how these pitchers have done: If a single A pitcher is in tier one or two, he's having a good year, and a AAA pitcher in tier three or four is not.