The lack of fans at NFL stadiums to start the 2020 season will rob the football world a great and recent tradition.

Every close call against the home team will no longer be followed by 80,000 sudden rules experts demanding their head coach throw the challenge flag. Nor will anyone boo when the referee inevitably announces the failure of said challenge.

There were 222 challenges in the NFL last season. That’s a bit less than one per game. Coaches were only correct on 83 of those challenges. It’s a success rate of just over 37% and a shocking (!) confirmation that referees know a lot more about the rules than the coaches.

Which coaches are the best at it? The worst? The most trigger happy on the challenge flag? A good football fan would probably be able to loosely guess the correct answers, but there are a few surprises.

Only eight of the active NFL coaches are even 50-50 at getting calls right and three of them (Kliff Kingsbury, Brian Flores and Matt LaFleur) only have one season of experience. The top five with more than one season at the helm look like this:

• Doug Marrone 22-37 (59%)
• Kyle Shanahan 11-19 (58%)
• Mike McCarthy 47-93 (51%)
• Mike Zimmer 19-38 (50%)
• Bruce Arians 24-48 (50%)

That’s right! Doug Bleeping Marrone is the smartest active NFL challenger in a top five that looks like it was pulled directly from a Sesame Street “Which of These Is Not Like The Other” segment.

Andy Reid is ninth the league with a 48% success rate (59-122). He and Bill Belichick are tied for the lead among current coaches at letting the challenge flag fly the most times. The Hoodie has only been correct 49 times (40% success-18th best active). Ron Rivera rounds out the active top ten with a 48% win rate.

Pete Carroll (12th, 42-91), Sean Payton (13th, 51-111) and John Harbaugh (16th, 46-105) are all also among the top half of the league in challenge success rate.

Buffalo’s Sean McDermott can be found on the other top five list. As in the five least successful challengers in the NFL (more than one season of experience):

• Sean McDermott 3-15 (20%)
• Matt Nagy 2-8 (25%)
• Mike Vrabel 3-10 (30%)
• Frank Reich 3-14 (31%)
• Jon Gruden 33-96 (34%)

Vic Fangio’s Oh-fer in his rookie season (0-4) is the only thing keeping McDermott out of the basement among all active current coaches.

Good thing McDermott has one of the best all-time challengers on his staff. (To make this list, you have to coach more than two seasons)

Leslie Frazier is one of three coaches all time who have been correct on at least 60% of challenges. Frazier was conservative taking his red flag from the holster with only 15 challenges in four seasons at the helm in Minnesota, but he picked his battles well. He was correct on nine challenges, including a 5-for-7 season in 2011. It was about the only thing Frazier won that year. Those Vikings were 3-13.

Dennis Allen (who?!?) has the all-time best success rate at 63%. He went 7-for-11 in three seasons winning eight of 36 games for the Raiders.

Jim Caldwell might be a better choice for the all-time coach’s challenge title belt, since he had a more legit NFL career with seven seasons coaching the Colts and the Lions. Caldwell was correct on 22 of 36 challenges (61%).

You know who was pretty darn good at challenges? Rex Ryan. He’s got the best single year going head to head with the referees, getting nine of ten correct in 2011. Ryan is barely one of the few over .500 for his career at 34 of 67. He was right on 11 of 18 during his two seasons in Buffalo (That tops even Challenge Guru Doug Marrone who went 6 for 12 while with the Bills).

The rest of the Bills coaches in the challenge era vary from pretty decent to forgettable: Dick Jauron 12-26, Mike Mularkey 7-18, Chan Gailey 6-15, Gregg Williams 7-24, Wade Phillips 4-15 (records in Buffalo only).

Phillips, curiously, was 17-31 challenging calls once he left Buffalo. He was a scorching hot 15 for 24 during his first three seasons in Dallas.

No one has questioned the referees more often than John Fox. He requested a review 133 times in 16 seasons and got a very respectable 48 correct. The busiest single season of challenges belongs to Mike Shanahan, who threw his red flag 18 times in 2005 and was right on 11 of them.

The only two coaches who have a worse success rate all-time than McDermott’s 20% are Dick LeBeau (3 for 18, 17%) and, stunningly, Dan Reeves. The longtime Broncos, Giants and Falcons coach is 10th in NFL history with 190 wins, but won a challenge only four times in 28 tries (14%).

The coach’s challenge began in 1999 and it was clear the early years were a struggle. Reeves only dealt with the rule for the last five seasons of his illustrious career. Joe Gibbs was wrong on 16 of 22 challenges. Dick Vermeil missed on 26 of 33 tries. Mike Holmgren whiffed 36 times out of 50.

On the flip side, the handful of coaches who have been right more than wrong in their career come mostly from the last decade. That list includes Tony Sparano (8-15), Jim Schwartz (15-27) and Chip Kelly (11-21).

The third decade of coach’s challenges likely won’t be much easier, but at least it will begin without a stadium full of back seat drivers and second guessers clouding any judgement.