The difference between winning and losing in the NFL can sometimes be traced back to a team's performance in the red zone. It's where offenses can turn a good drive into a great one, and it's where defenses can save precious points by forcing field-goal tries rather than giving up touchdowns.

It's also the toughest area on the field for quarterbacks as the condensed space results in smaller throwing windows.

After looking at which quarterbacks were the best in this area of the field in 2017, who were the worst?

We can figure out which quarterbacks were the least efficient in the red zone by using our Net Expected Points (NEP) metric -- specifically Passing NEP per drop back, which accounts for sacks as well as pass attempts.

We use NEP to track the efficiency of both teams and players with the team side being adjusted for strength of opponent. It helps us see the difference between a three-yard completion on 3rd and 2 and a three-yard completion on 3rd and 4. NEP also helps account for that by tracking the expected points players add to their team's total over the course of a season. You can learn more about NEP in our glossary.

We will be looking at players who attempted a minimum of 30 red zone passes last season. This cut off point disqualifies Houston Texans quarterback Tom Savage, who only completed 8 of his 28 red zone pass attempts last season.