For what seems like football eternity, we’ve defined turnovers in two ways: fumbles and interceptions.

Those are the truest forms of giveaways, essentially delivering the ball to the opponent, but they’re not the only ones. So why haven’t we expanded our definition of the turnover term sooner? Why aren't we counting all forms of giving the ball up? Right now, that tried-and-true definition simply isn’t complete enough when looking at the big picture of football.

So let’s say we change that. Fumbles and interceptions are half of the equation. The other side of the coin: missed field-goal attempts and failed fourth-down attempts. They're just as important when considering how many net possessions a team gives up.

Makes sense, right? A team misses a field-goal try, and the opponent gets the ball at that spot. Same idea with fourth downs: You hear announcers all the time say that a team “turned it over on downs,” so why shouldn’t we count those as turnovers as well?

We decided to do just that at Pro Football Weekly this season. We are calling it the “True Turnover metric” — and who knows, maybe we’ll come up with something snappier sounding down the road. But for now, this works. And we'll be charting this all season on a weekly basis to look for trends and insight into why certain teams are performing the way they are.

The idea is to take a broader, more complete look at the number of times a team comes up short on possessions that don’t involve a punt. (Perhaps we also could throw blocked punts into that mix, too, but that feels more like a different type of breakdown or standout play, depending on the perspective. Plus, they’re rare enough to where it wouldn’t skew the numbers enough that we are leaving them out for now.)

Let’s first look back at the True Turnover numbers for the 2017 season for some perspective. Again, for clarity, the formula is simple: each team’s net turnovers forced (intercepted passes, opponents’ fumbles recovered, opponents’ missed FG attempts and opponents’ failed fourth-down conversions) minus its own net turnovers (passes intercepted, lost fumbles, missed FG attempts and failed fourth-down conversions).

Easy peasy. Here's the 2017 data:

For teams with bad kicking situations, it can mean an extra possession or two lost per game; or for aggressive-minded teams that come up short often, the same result. Likewise, there are teams that get lucky with opponents’ missed FG attempts, or perhaps they play very good fourth-down defense. This can help us go beyond the standard numbers to determine why certain teams can do well despite not gaining a lot of yards or despite having a leaky defense most plays but can win games simply by stealing a possession or two per game.

This falls under the all-important definition of “hidden yards” that often tells the tale of why teams can win or lose despite large disparities in yards gained vs. yards allowed.

Some quick thoughts on the 2017 True Turnover results and what they meant:

• The Ravens led the NFL in standard turnover differential (net fumbles and interceptions) at plus-17, and they were first on the True Turnover table at plus-23. But those net six extra possessions can’t be overlooked. They were 9-7 last year and a wild conversion away from 10-6 — and a spot in the playoffs — despite an offense that ranked 31st in yards per play, 27th in third-down conversions and 23rd in red-zone efficiency. That’s one reason why I felt the Ravens this season were improvement candidates with upgrades on offense.

• The Patriots were only plus-6 by the standard table (11th-best in the NFL) but were second to the Ravens on the True Turnover Table at plus-20. That perhaps explains why New England could reach the Super Bowl with a defense that performed as poorly much of last season as it did. The Patriots’ offense received more than an extra try to score per game.

• On the surface, the Packers’ 2017 standard turnover ratio of minus-3 tied for 20th in the NFL last season, essentially lumped into the league’s lower-middle class, but hardly worrying. However, their True Turnover numbers are far more enlightening about why they went 7-9 last season — and yes, we have not forgotten about Aaron Rodgers’ injury. The Packers were a whopping minus-15 on the True Turnover scale, mostly thanks to a huge disparity between their own 13 failed fourth-down attempts and their opponents’ three missed fourth downs.

• Another team with a big disparity between the old turnover table and True Turnovers: the Panthers, who registered a minus-1 if we just count fumbles and INTs but a plus-10 when we factor in field goals and fourth downs. That ranked as the 10th-best figure in the league, and it perhaps sheds more light on why the team went 11-5 last season and was exceptional in close games (a stunning 8-1 record in contests decided by eight points or fewer).

In Week 1 this season, there were some telling numbers as well:

• Our lowly 2017 Browns? Well, they now are tied for second in the NFL through one game this season at plus-4 in True Turnover differential — a terrific start for Gregg Williams’ defense as they welcome so many new faces on the other side of the ball.

• Clearly the Lions know what went wrong in Week 1 against the Jets. If you said “pretty much everything,” you really wouldn’t be wrong. But in addition to Detroit’s five interceptions, they also gave away four other possessions (two missed field goals, two fourth-down failures) for a shocking net of minus-6 in a single game. For a head coach in Matt Patricia who was steeped in such a disciplined culture in New England to have his team turn in such a wretched, mistake-filled opener, it’s absolutely bizarre and stunning. The Lions were 10th in the NFL in True Turnover ratio in 2017, at plus-10.

• Speaking of the Patriots, they lost a mere four fumbles all last season but coughed up two in Week 1. In fact, their three opening-game turnovers were the most they’ve had since Week 14 of the 2016 season. Under Bill Belichick, the Patriots have had three or more turnovers only 43 times in his 289 games (14.9 percent) as Patriots coach. Their 20 True Turnovers (eight coming on field goals and missed fourth downs) last season were the fewest in the NFL — by six. A bit un-Patriots-like performance this first game. They historically just don’t give the ball away so freely like they did against the Texans.

• Three teams failed on two fourth-down conversions in Week 1: the Lions, Titans and Giants. The Giants went for it on 4th-and-2 from the Jacksonville 38-yard line midway through the third quarter and came up a yard short. Right call, we say, but just bad execution. The second failure came in a clear go-for-it situation, down 20-15 with 1:55 left in the game at the Jacksonville 36. Those two plays might have been the difference between winning and losing in Giants head coach Pat Shurmur's debut against a good Jaguars team that had them on the ropes early.

• You might not have remembered the Titans’ first fourth-down failure in the game, and we can hardly blame you considering two long weather delays stretched that contest out to an NFL-record seven hours, eight minutes. But that stop came late in the first quarter when Marcus Mariota hit Corey Davis on a short pass on 4th-and-goal from the Miami Dolphins’ 3-yard line, but Davis couldn’t get into the end zone. That was seven points lost right there. The Dolphins had their own fourth-down failure a quarter later on a 4th-and-1 from the Tennessee 15 that came up empty, so it was a net-zero at that point and a huge stop for the Titans, at the time trailing 7-3. The Titans’ second turnover on downs was some five real-time hours later, trailing by 10 with just over three minutes left in the game when Blaine Gabbert couldn’t convert a 4th-and-7 on their own side of the field. Don’t overlook how big that one was; despite having burned all their timeouts, the Titans actually got the ball back and made it a one-score game before Miami recovered the onside kick in the waning seconds.