The NFL's official measure of passing efficiency, adopted by the league in 1973. It combines four per-attempt rates — completion percentage, yards per attempt, touchdown rate and interception rate — each scaled and capped so no single component can dominate. The result runs from 0.0 to a maximum of 158.3, the so-called perfect rating.
The college (NCAA) passer-efficiency rating uses a different, uncapped formula on a different scale; the two numbers are not comparable.