Chapter 1: The Real Number System
Numbers in the Real World

Stat the Quarterback


In football at any level, the position that gets the most attention is the quarterback.  The NFL has developed a rating system to evaluate the performance of quarterbacks.  Since the primary focus of a quarterback is passing, the rating is based on the results of passing: attempts, completions, yardage, touchdowns, and interceptions.  The rating system is outlined below.
 

Quarterback Rating System
Step 1:  Complete passes divided by pass attempts.  Subtract 0.3, then divide by 0.2 
Step 2:  Passing yards divided by pass attempts.  Subtract 3, then divide by 4. 
Step 3:  Touchdown passes divided by pass attempts, then divide by .05. 
Step 4:  Start with .095, and subtract interceptions divided by attempts.  Divide the product by .04.
The sum of each step cannot be greater than 2.375 or less than zero.  Add the sum of Steps 1 through 4, multiply by 100, and divide by 6.

Below are the stats for Elvis Grbac, Kansas City Chiefs QB, for the first 4 games of the 1997 NFL season.
 

Elvis Grbac
Pass Attempts Pass Completions PassYardage Touchdown Passes Interceptions
126 71 830 6 2

Use the steps listed above to compute his rating.
Step 1
Step 2
Step 3
Step 4
Quarterback Rating

Check Your Answers

Find the stats of your favorite quarterback and compute his quarterback rating.  You can find quarterback stats on the statistics page for individual players at the Sporting News site.

As a class, have each student choose a quarterback and continue to compute the quarterback efficiency rating every week.