Nobody would ever watch the NBA and argue that DeAndre Jordan was a more accurate shooter than Steph Curry. If you look at the raw numbers, Jordan has a higher field goal percentage than Curry. In the NFL, that would be enough to say that Jordan was “more accurate” than Curry.
Fortunately the NBA has a three-point percentage and in recent years has developed an Effective Field Goal Percentage that accounts for twos and threes together.
The numbers on this page work under the same principle. Passes that were completed behind the line of scrimmage count for nothing. For every yard the ball goes past the line of scrimmage, 0.1 is added to the quarterback’s adjusted completions number. So a one-yard pass is 0.1, an eleven yard pass is 1.1 etc etc. This chart still can’t account for drops or inaccurate throws that were caught. For that accuracy percentage you can purchase the Pre-Snap Reads Quarterback Catalogue.