The Most Important Stat in Football

Here’s everything you need to know about the metric to be an expert.

The Most Important Stat in Football

Kansas City Chiefs quarterback Patrick Mahomes is building a Hall of Fame career.

Bud Goode (pronounced "goody"), the father of pro football analysis, was a mathematician at heart who spent almost half a century collecting and analyzing football statistics. One sportswriter called him "a Hollywood press agent loose in a Twilight Zone of numbers."

In 1973, he predicted the winners in 75 percent of the NFL games played. He often said he wanted the inscription on his headstone to read: "Here lies Goode. He told the world about average yards per pass attempt." He died in 2010.

He may not have gotten his tombstone wish, but yards per pass attempt — today known as net yards per pass attempt, or NY/A — remains the most important stat in pro football.

Here’s everything you need to know about the metric to be an expert. Or at least impress your friends, family and coworkers.

12 Super Bowl Winners

From 1985 through 2010, Goode did research for 26 NFL franchises, including 12 Super Bowl winners.

Among his most devoted followers were his first, George Allen (with both the Redskins and the Rams), Dick Vermeil, Bill Parcells and Bill Walsh.

All four took teams to the Super Bowl, and the last three coaches won.

Against the Odds

Bud Goode in a photo for a 1974 Sports Illustrated article that put him on the football map.

The football establishment first took notice of Goode when Sports Illustrated’s Joe Marshall profiled him before the 1974 Super Bowl between Minnesota and Miami.

Many analysts favored the Vikings by three points, but Goode’s algorithm was emphatic: Miami was better than Minnesota and would win by at least nine.

The Dolphins won handily, 24-7.

A Simple Stat

Indianapolis Colts quarterback Peyton Manning throws a pass during a 2002 game against the Philadelphia Eagles in Philadelphia.

Goode used several yardsticks in his evaluation, but the most important, the one he found that best correlated with winning, was net yards per pass attempt, or NY/A, simply the net yards a team passes for divided by the number of attempts.

(Passing Yards – Sack Yards) divided by (Passes Attempted + Times Sacked)

Peyton Manning used to be the NFL career leader in net yards per pass attempt at 7.23. Now, it's Patrick Mahomes at 7.48.

How It Works

New Orleans Saints quarterback Drew Brees, center, reacts after throwing a touchdown pass during a 2018 game against the Washington Redskins in New Orleans.

Simply put, if Team A threw 30 passes for 250 yards and suffered three sacks for losses of 30 yards, they have a net gain of 220 yards on 33 attempts, for a 6.66 yards per attempt.

If Team B averaged, say, 5.6 yards an attempt (or NY/A), then Team A probably won the game.

How Often Does This Hold True?

Kansas City Chiefs quarterback Patrick Mahomes ranks among the YPA leaders in 2018.

What’s the probability of yards per pass attempt determining final results?

If you want to impress your football friends, try this trick. Next Monday morning, ask someone to look at the NFL box scores. For each game, tell them not to tell you the teams or any other information except the number of net yards each team passed for, number of sacks and sack yardage, and the number of pass attempts.

With that alone, you can tell them who won the game four out of five times, or around 80 percent.

The Second Most Important Stat

Green Bay Packers quarterback Aaron Rodgers has a career interception percentage of 1.5.

The second most important stat that correlates with winning is interception percentage.

The lower the interception percentage, of course, the better.

NY/A Over the Years

Baltimore Colts kicker Steve Myhra (65) makes a field goal with 10 seconds left in the 1958 NFL championship game against the New York Giants to tie the score at 17 and send the game into overtime at Yankee Stadium in New York City. The Colts won 23-17 to take the title in what is widely known as "The Greatest Game Ever Played."

In the 1990s, my colleague, statistician and economist George Ignatin, tested Goode’s theory all the way back to 1958, the year which many regard as the birth of the modern NFL, when Johnny Unitas led his Baltimore Colts to a thrilling sudden-death victory over the New York Giants in the championship game.

The NFL started keeping better and more comprehensive stats that year, so football was easier to study.

Since then, diligent stats gurus have poured over thousands of box scores and updated NFL stats back to 1932.

History Backs Goode Up

Dallas Cowboys quarterback Roger Staubach looks to throw a pass in a 1979 game against the St. Louis Cardinals in Dallas, Texas.

Goode was absolutely correct: Pro football essentially was a game of passing and pass defense, and the best stat for measuring the effectiveness of the passing game was yards per pass attempt. In our study, the team that had the highest NY/A for that game won 83 percent of the time.

In 2008 we updated, and the margin had dropped slightly to 81.5 percent, which a statistician would call an acceptable statistical variation.

We did it again in 2015, and the wins rate was 81.8 percent.

Best NY/As Dominate the Super Bowl

Philadelphia Eagles quarterback Nick Foles is pressured by New England Patriots defenders during Super Bowl LII on Feb. 4, 2018, in Minneapolis. The Eagles ranked third in the NFL in NY/A at 6.2 yards for the 2017 season. The Patriots ranked second in NY/A at 7.1. Philadelphia won the game 41-33.

In the last 10 Super Bowls, 12 of the 20 teams who made it to the big one were in the NFL’s top five in NY/A and 15 of the 20 were in the top eight.

Football Is a Game of Passing

Pittsburgh Steelers quarterback Terry Bradshaw winds up to throw a pass during Super Bowl XIII against the Dallas Cowboys in Miami on Jan. 21, 1979. Bradshaw led Pittsburgh to four Super Bowls wins.

Why was the success rate so steady?

With all the possible variations in football — including running, punting, placekicking and kick returns — why was a simple passing stat by far the most important?

Because pro football, at least since the time of Unitas, has been a game of passing and pass defense.

Average Yards Per Rush Is No Measure of Success

Los Angeles Rams running back Todd Gurley pushes away Seattle Seahawks outside linebacker K.J. Wright during a 2018 game in Los Angeles.

It’s not that NFL running backs aren’t good. They are very good, and in fact, they’re all very good.

In the NFL, the average yards per rush is almost always between 4.0 and 4.2, but there is little correlation between winning and losing and being above or below that average.

In the 2018 season, so far, it’s 4.4.

Take the 1958-1959 Colts

Baltimore Colts fullback Alan Ameche runs through a big hole to score the winning touchdown in overtime against the New York Giants in the 1958 NFL championship game at Yankee Stadium in New York.

For example, in 1958, the Colts, with their great running backs Alan "The Horse" Ameche and Lenny Moore, averaged 4.7 yards per rush while the league as a whole averaged 4.2.

But in 1959, the Colts also won the NFL championship, and at 3.9, they were below the league average of 4.2.

The Packers Also Won on Passing

Green Bay Packers vs. Dallas Cowboys in 1967 — Green Bay Packers fullback Jim Taylor runs with a Bart Starr pass against the Dallas Cowboys in the NFL championship game on Jan. 1, 1967 in Dallas, Texas. The Packers beat the Cowboys 34-27.

Vince Lombardi’s best Green Bay Packers team won the title in 1962. Led by their Hall of Fame running backs Jim Taylor and Paul Hornung, the Pack averaged 4.7 yards per rush to the league’s 4.1.

But in 1966, the Packers won the title again and were tied for dead last in the league in yards per rush at 3.4, while the league averaged 3.9.

That’s the way it’s been over at least 60 years.

Establishing the Run Not the Key

One of the most efficient signal-callers in NFL history, Joe Montana completed over 63 percent of his passes over a 15-year career.

Pro football as we know it has always been a passing game, or at least a game of passing efficiency.

During broadcasts, commentators often insist, "You have to establish the run."

They should be saying, "Establish the pass and then, when you get a lead, use the run to eat up the clock."

Unitas Was Efficient

Johnny Unitas was not only the most prolific passer of his era. He also was one of the two most efficient, leading the league in yards per attempt, or Y/A, three times.

This is a slightly different stat than the NY/A teams are measured by. Quarterbacks shouldn’t be penalized for getting sacked, so Y/A , simple yards gained passing divided by throws, is a fairer way to evaluate them.

Otto Graham is the career leader in yards per attempt at 9.0.

Bart Starr Led the NFL Twice

The other efficient passer of the Unitas era was his great rival, Bart Starr, who led in Y/A twice.

In the 1966 campaign, Starr took his Packers to the NFL championship and victory (over the Kansas City Chiefs) in the first Super Bowl by throwing just 14 touchdown passes during the regular season. But he led the NFL with an average of 9.0 Y/A.

The Underrated Stat Is Yards/Attempt

Los Angeles Rams quarterback Jared Goff throws a pass during a 2018 game against the Green Bay Packers in Los Angeles.

Net Yards Per Pass Attempt (NY/A) is one of the most underrated stats in pro football.

Nowadays, most football websites include yards per attempt, but you can watch entire games without hearing them mentioned.