It's the carrier's portion of the CSA (they deleted 2010) score.
If I were looking to change carriers I'm thinking that I would check out this information about prospective carriers. It provides information on all carrier wide inspections done over the last 24 months. I wouldn't want to lease on with a carrier that has high scores. It would make me a target for DOT officers.
It is some very entertaining reading with all the orange alert boxes on these 5 star carriers. If yer thinking of changing carriers you might be surprised at who would be left off of the short list.