What is a quality opponent? 
The Cold, Hard Football Facts define a quality opponent as any team that currently has a winning record.
What is a quality win?
The term "quality win" simply refers to a victory against a quality opponent (that is, a victory against a team with a winning record).
What are the quality standings?
These are simply a team's standings against opponents who currently have a winning record.
When do you get credit for a quality win?
You get credit for a quality win any time you beat a team with a winning record, and for as long as that team continues to have a winning record.
For example, if Team A beats an opponent that was 3-0 in Week 4, it qualifies as a quality win in Week 4 and for as long as that opponent has a winning record. However, if that opponent is 4-4 after Week 8 (or 4-5 after Week 9), they no longer qualify as a quality opponent and Team A's victory against them no longer qualifies as a quality win. If said opponent ends the season 10-6, Team A gets credit for a quality victory in the end-of-year standings. If said opponent ends the season 8-8 or worse, Team A does not get credit for a quality victory in the end-of-year standings.
Shouldn't you get credit for beating a winning team, no matter how they end up?
No. It might look pretty impressive to beat a 4-0 team. And many people argue that you should get credit all season for a quality victory, no matter how that 4-0 team ends up. But we disagree and stand by our formula.

Here's why: If that 4-0 team ends up 7-9, it tells us that the one-time 4-0 team really wasn't that good after all. Our study of the Quality Wins Quotient tells us that an opponent who once stood at 4-0 probably faced a very weak schedule early in the season.
Generally speaking, long win streaks in the NFL are the result of easy schedules. Long losing stretches are the product of tough schedules. The 2004 season provided a perfect case study of this phenomenon of scheduling. Take Carolina. The Panthers poorly defended their 2003 NFC title by stumbling out to a 1-7 record in the first half of the season. Sure, the Panthers were ravaged by injuries. But they also faced six quality opponents in those first eight weeks. They lost all six games. Carolina promptly recovered with a 6-2 record in the second half of the season, earning the respect of the entire NFL in the process. But their schedule over the final eight weeks included just one quality opponent (11-5 Atlanta). The Panthers lost that game. In other words, the Panthers had a great record against bad teams (7-2) and an awful record (0-7) against quality teams.
Buffalo made a late-season playoff run in 2004 with an impressive six-game win streak. But they faced just one quality opponent – a borderline quality 9-7 Seattle team – in that six-week period.
What's the purpose of the Quality Wins Quotient?
The Quality Wins Quotient gives us a much better idea of the relative strength of teams than does overall record.
Essentially, if you strip away the dead-weight detritus of games against NFL also-rans and look only at how teams perform against quality opponents, you're left with a stark, naked look at the essence of a team – minus the mid-season stat-padders against NFL cellar dwellers. Who fixes bayonets when the sh*t gets heavy and the ammo runs low? Who cowers in their foxhole and lifts the white flag? The Quality Wins Quotient will tell you.
Overall records can be highly misleading. Quality standings are not. San Diego gave us a prime example in 2004. Sure, they were 12-4 overall. But against quality opponents they were 2-4 and gave up more points per game than they scored. This means they padded their record with a 10-0 mark against teams that were 8-8 or worse. San Diego was promptly bumped from the playoffs in the first round, despite having home-field advantage against a 10-6 Jets team. It was no surprise to us. The 2004 Jets had a better record and a better scoring differential against quality opponents than the Chargers.
Does the Quality Wins Quotient work?
It worked anecdotally over the years as we tracked playoff teams. We put it to the test of public scrutiny for the first time in the 2004 playoffs. It worked like a $10 whore at happy hour. Teams with better overall records went 7-4 in the postseason. Teams with better records against quality opponents went 10-1 (and 8-3 against the spread). The Quality Wins Quotient also accurately called for three wins by road underdogs in the first round of the playoffs. Never before in NFL history had three road underdogs won playoff games on the same weekend. But it happened in 2004, just as the Quality Wins Quotient had predicted.
The only game the Quality Wins Quotient failed to call accurately in the 2004 playoffs featured the closest margin possible: Atlanta and Philly each went 2-1 against quality opponents in 2004. Atlanta had a point differential that was a mere 0.3 PPG better than Philly's. Philly, of course, beat Atlanta. However, knowing that Atlanta, a dome team, was playing on the road in chilly Philly, the razor-thin quality wins margin would have prompted most people, including us, to eschew the Quality Wins Quotient if we had money riding on the game.
Remember, though: Past performance is no guarantee of future results.
Does the Quality Wins Quotient have flaws?
Yes. It really doesn't work well early in the season. In fact, it won't be until Week 3 that a team can get credit for even a single quality win. But it does improve steadily as the season goes on, and we get a better idea for which teams are truly the quality teams and which teams are the also-rans. However, the Quality Wins Quotient will begin to show trends in the first month of the season and will do a better job than overall record of helping you separate good teams from bad teams.