A statistic in football that measures the rate of a quarterbacks pass attempts that lead to a first down, which gives an indication to how well a quarterback is able to move the ball down the field for the team and generate a new set of downs. The higher the Passing First Down Percentage the better.
Formula: Passing First Down Percentage = passing first downs / passing attempts
For example, during the 2012 NFL season, Atlanta Falcons QB Matt Ryan threw for 246 first downs on 615 passing attempts for a passing first down percentage of 40.0% while Chad Henne of the Jaguars threw 85 first downs on 308 attempts for 27.6% passing first down percentage.
In general, this statistic gives an indication of the skills of the quarterback at passing but is also dependant on the quality of the team overall including the receiving core as well as the overall passing strategy.