QB Wins is a weak, inadmissible "stat"
Over the past few years, the QB Wins "stat" has emerged as a metric that fans and media love to use to compare the success of quarterbacks. They use this "stat" as a "fair" method of comparing these players and their influence to their teams, when it really just pushes the narrative of highlighting certain players. It has become a common school of thought, but I have always thought QB Wins is a lazy metric and should not be used in a valid argument. Here are a few reasons why:
QB wins can sometimes completely ignore the quarterback's actual performance
Because of the nature of the stat, a QB could have a season where he throws for over 5000 yards with 35+ TD and a low number of interceptions but still struggle in the QB wins category. All it would take is a bad defense or a team that finishes under .500 for some reason. QB wins blames the outcome of every play on the quarterback, which is just simply not accurate.
In 2000, Jeff Garcia was named a Pro Bowler after throwing for 4278 yards (2nd most), 31 TDs(3rd most) , and just 10 interceptions. Good enough for a 97.6 passer rating. The 49ers still went 6-10 that year thanks to a 28th ranked defense. It's safe to say Garcia did all he could to win those games, yet he's the one punished with this "stat."
It ignores all other influential game factors
That brings me to my next point. QB wins completely ignores all other factors that can or do influence the outcome of the game. Yes, quarterbacks can have miraculous drives to win a game, but there are more often times that something else happens late in the game causing the team to lose. It could be a receiver dropping a perfect pass, a running back fumbling on the goal line, or a defense giving up the go ahead score with almost no time left. Think of all the weird ways games have been won. I think we can all agree the losing QB should not be at fault unless it was a resulting directly from his performance.
It ignores the quality of opponents
The formula for QB Wins is simple: if you start a game at QB and your team wins, you get a QB win. There's nothing more to it. So, if a great team plays a weak schedule, their QB will probably have more QB wins by the end of the season than the quarterback for a good team playing a hard schedule. This benefits QBs in weaker divisions because they get to play bad teams twice.
It basically compares one player (the QB) to an entire 53 man opposing roster
In reality, QB Wins is just rephrasing the term "win" by placing all the blame/credit on the QB. But isn't a "win" a stat that applies to the result of the entire team? When using QB wins as a basis of argument, you're essentially dropping his 52 teammates, ignoring other phases of the game, and comparing his ability to win against a entire 53 man roster. 1 against 53 is never a fair fight. While some players have shown the ability to carry teams, football is still a game that is won by teams. A player's performance can help get a win, but you still win as a whole.
Average QBs can have good QB wins marks while being carried by great defenses.
I'm sure you've heard the old saying "Defense wins championships." Many teams over the years have won Super Bowls with below average to average quarterback play because of their defenses. No team illustrates this better than the Baltimore Ravens (pre- Lamar Jackson). In 2000, the team won the Super Bowl with career back up Trent Dilfer at the helm. They dominated the Giants thanks to a stellar defense led by Ray Lewis. The Ravens would be a dominant team for the better part of the next 20 years, while Dilfer went back to being a back up. Additionally, the Jets had some good years with low-end QBs Chad Pennington and Mark Sanchez under center. There are more cases, but you get the picture.
Similarly, QB Wins can be influenced by great defenses. A good example of this is Joe Flacco. Now, Flacco has never been a bad quarterback. He's extremely consistent and a capable starter, but he's never put up the kind of stats you would expect from an influential position. Flacco currently ranks 18th in QB wins in NFL history (ahead of guys like Troy Aikman, Len Dawson, and Steve Young), yet only has one season with 4000+ passing yards and rather pedestrian touchdown numbers. He did win a Superbowl in 2012, but the Ravens leaned mostly on their defense and running offense.
Conclusion
I'm sure whoever decided QB Wins was a "stat" had good intentions. After all, we are always looking at ways to compare players to each other to figure out who's the best. I just think it's a faulty stat. It could be improved on by incorporating elements such as strength of schedule,defenses, and overall teams. For now, I think the best comparisons are head to head results and performances against common opponents.