Passer rating (also known as quarterback rating, QB rating, or passing efficiency in college football) is a measure of the performance of passers, primarily quarterbacks, in American football and Canadian football. There are two formulae currently in use: one used by both the National Football League (NFL) and Canadian Football League (CFL), and the other used in NCAA football. Passer rating is calculated using a player's passing attempts, completions, yards, touchdowns, and interceptions. Since 1973, passer rating has been the official formula used by the NFL to determine its passing leader.