Pass efficiency

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. Passer rating in the NFL is on a scale from 0 to 158.3. Passing efficiency in college football is on a scale from −731.6 to 1261.6.

Before the development of the passer rating, the NFL struggled with how to crown a passing leader. In the mid-1930s, it was the quarterback with the most passing yardage. From 1938 to 1940, it was the quarterback with the highest completion percentage. In 1941, a system was created that ranked the league's quarterbacks relative to their peers' performance. Over the next thirty years the criteria used to crown a passing leader changed several times, but the ranking system made it impossible to determine a quarterback's rank until all the other quarterbacks were done playing that week, or to compare quarterback performances across multiple seasons. In 1971, NFL commissioner Pete Rozelle asked the league's statistical committee to develop a better system. The committee was headed by Don Smith of the Pro Football Hall of Fame, Seymour Siwoff of the Elias Sports Bureau, and NFL executive Don Weiss. Smith and Siwoff established passing performance standards based on data from all qualified pro football passers between 1960 and 1970, and used those data to create the passer rating. The formula was adopted by the NFL in 1973.

The NFL passer rating formula includes four variables: completion percentage, yards per attempt, touchdowns per attempt, and interceptions per attempt. Each of those variables is scaled to a value between 0 and 2.375, with 1.0 being statistically average (based on league data between 1960–1970). When the formula was first created, a 66.7 rating indicated an average performance, and a 100+ rating indicated an excellent performance. However, passing performance has improved steadily since then and in 2017 the league average rating was 88.6.

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