The quarterback is first among equals when it comes to a football team’s offense. This is not shocking. They’re the decision-makers on the field, the one player who is almost guaranteed to have the ball in his hand in the course of every play (let’s pour one out for the Wildcat). Even when a QB gets derided as a mere “game-manager,” the not-quite slur acknowledges that even the most passable of quarterbacks is in charge of making the offense go.

As the head of operation: Points on the Board, a National Football League quarterback is up against every other NFL quarterback whenever they take the field. It’s inevitable. Due to a QB’s status, he is largely held responsible for every loss and every victory. In some order, it will be the head coach, the quarterback, and a defense (either a team’s own or the other team’s) that will be credited for the outcome of every game.

But which quarterback in NFL history is the best? What really constitutes the best? How could anyone ever know? FootballPerspective.com took a crack at tackling this difficult question, and the site seems to have done a pretty good job.

Deciding that one great season wasn’t enough to hang a career on (consider Tebow in 2012 compared to Tebow in 2014), the site took each NFL quarterback’s five best seasons and ran them through a self-proclaimed “quick-and-dirty formula.

Calculate the relative ANY/A (adjusted net yards per attempt) of each quarterback in every season since 1950; for each quarterback season, multiply each quarterback’s number of dropbacks by his relative ANY/A to derive a passing value over average metric; pro-rate non-16 game seasons to 16 games; and calculate a career grade for each quarterback based on the sum of his best five seasons.”

Sound like a lot of math? It is a lot of math. The results, though, are not nearly as complicated as the process. Check it out.

5. Steve Young: 6,028 adjusted net yards over average

Best seasons: 1991, 1992, 1993, 1994, 1998

No one’s surprised that Steve Young is on the list. If anything, they’re surprised he’s so low. With separate entries into the College Football Hall of Fame and the NFL Hall of Fame, “Grit” is still holding on to the third-highest passer rating in NFL history, and he’s still holding on to his six passing titles.

So why only slot No. 5 for the 49ers legend? It goes back to the method and adjusted net yards per attempt. What’s an adjusted net yard per attempt? According to Football Perspective, it’s “(Passing Yards + 20 * Passing TDs – 45 * INTs – Sack Yards Lost) divided by (Pass Attempts + Sacks).” Make sense?

Steve Young’s 1994 season looks like this: 3,969 yards and 35 touchdowns with 461 pass attempts, 10 interceptions, and 31 sacks for 163 yards lost. Or: (3,969 + 20*35 – 45*10 – 163) divided by (461 +31), which is 8.24. So Steve Young had an ANY/Y of 8.24 in 1994. Subtract that from the league average ANY/Y from that year to get the Relative ANY/Y.

Then, the Perspective folks multiplied that number — which you can find on Pro-Football-Reference in case you don’t want to do the math yourself — by the number of dropbacks a quarterback had that season, and boom: Young scores a 1,410 in 1994, a 1,342 in ’92, a 1,202 in ’93, a 116 in ’98, and a 904 in ’91. Add those together, and you get 6,028, good for fifth all time. Easy, right?

4. Dan Marino: 6,163 adjusted net yards over average

Best years: 1984, 1986, 1987, 1988, 1992

Dan Marino, the nine-time Pro Bowler and five-time passing leader (who is still the all-time leader for game-winning drives), comes in at No. 4 with the Football Perspective’s system — because you can’t keep a good Dan down.

How do the ANY numbers compare to the real numbers? Well, in ’84, the Dolphins got off to a blazing start, reeling off 11 straight wins before finally losing, in overtime, to the San Diego Chargers. They made it all the way to the Super Bowl but lost to the 49ers. In ’86? They went 8-8, missing the playoffs, but Marino went nuts, averaging almost 300 yards a game and racking up the second-highest AV (approximate value — if you had to boil down a player to one number) of his career.

His best year of the bunch was 1984, with an ANY/A of 2,271. That was his 45-touchdown year, when the Dolphins almost went all the way. Check out some of Marino at his prime right here — it’s all his TDs in one place, plus some hilariously classic interview footage from coach Don Shula and the Marinimal himself. Also, be glad that football on television has evolved in leaps and bounds over the past 30 years.

3. Drew Brees: 6,592 adjusted net yards over average

Best years: 2006, 2008, 2009, 2011, 2013

Who’s that? That’s Drew Brees, one of the most pass-happy quarterbacks to ever make it to the NFL. It’s not a shock to see Breesus ranked this highly on any list that’s based on any kind of “he throws the football better than most” list, but did you really expect last season to make an appearance on his best ever? You don’t have to lie.

In the 2013 season, the Saints went 11-5 and made a strong push into the playoffs — until they, like everyone else, got shot down by the Seattle Seahawks — behind the return of Sean Payton, absent last year owing to BountyGate, and the rocket arm of No. 9. Climbing more than 5,000 yards thrown for the third straight season, Brees was able to pull off an A.N.Y./A of 1,123. Not bad.

His best year was 2011, when he threw for 5,476 yards on 468 completions (both best in the league that season) for an ANY/A of 1,590. The Saints got knocked off by the 49ers in the playoffs. So it goes. Here he is at his best.

2. Tom Brady: 6,853 adjusted net yards over average

Best years: 2007, 2009, 2010, 2011, 2012

Again, a pass-happy QB, high ANY/A rating. The interesting thing about Tom Brady is how many different systems he’s been able to rock the rocket arm. Think back to that ridiculous 2007 season. Brady to Moss. Brady to Moss. 16-0. Deep bomb after deep bomb. So on and so forth. Absurdly awesome offense doing incredible things on the football field. We all know that.

That team bears almost no resemblance to the 2012 squad, which was well on its way to blazing a new offensive trail with a pair of hyperathletic, pass-catching tight ends in Rob Gronkowski and Aaron Hernandez. Now, of course, Hernandez is in jail for life and Gronkowski misses more games than he plays.

Consider that for a second. Brady, more than any other QB in modern history, has been able to continually refine his game and his system (coach Bill Belichick deserves a lot of the credit here, too) to match up with his declining arm strength. Joke about deflation all you want, but the team that won the 2014 Super Bowl is far removed from prior successful years.

Here are some Brady highlights from 2007. Give it a look and see just how different that offense is from 2012.

1. Peyton Manning: 8,115 adjusted net yards over average

Best years: 2003, 2004, 2005, 2006, 2013

It’s not even close. Peyton Manning is the best passer in NFL history, and that was true before he went on the warpath with the Denver Broncos in 2013, burning down the offensive record book and replacing it with a portrait of Peyton. (Of course, Seattle promptly went back and replaced that painting of Manning with Manning Face).

That wasn’t his best season, though. As a passer, Manning’s best year was 2004, when he dropped an ANY/A score of 2,113. To put it in perspective, Brady’s 2007 notched a 2,014, and Manning’s 2013 was worth 2,031. Check it out below, and remember: They lost to the Patriots in the playoffs that year.

Statistics courtesy of FootballPerspective.com and Pro-Football-Reference.com.

For a complete, sortable quarterback list, courtesy of Football Perspective, click here.