NFL scouting departments spend millions of dollars each year evaluating quarterback talent.

Most teams have at least three levels of scouts to check, cross-check and re-check the players they are evaluating, but over the eight-year period from 2008-14, NFL teams hit on only five of 21 quarterbacks selected in the first round as franchise quarterbacks.

“Of that group, there are either four or five franchise quarterbacks,” NFL Network analyst Mike Mayock said. “There’s Matt Ryan, Matt Stafford, Cam Newton, Andrew Luck, and if you want to put Joe Flacco in there.”

Flacco is the only one whose team has won a Super Bowl title. Ryan and Newton have taken teams to the big game.

Some of the franchise-quarterback misses include Jacksonville’s Blake Bortles, Miami’s Ryan Tannehill, San Francisco’s Blaine Gabbert (Jacksonville draftee), San Francisco’s Christian Ponder (Minnesota draftee), Buffalo’s E.J. Manuel, Cleveland’s Robert Griffin III (Washington draftee) and Mark Sanchez (Jets draftee). There are nine others who aren’t in the league anymore.

“We did a study, and the best teams are batting .560 on all of their (draft) choices,” Hall of Fame executive Bill Polian told The Atlanta Journal-Constitution. “That’s total acquisitions and that includes collegiate free agency. The worst teams are in the .450 range. The fact of the matter is that you’re going to miss 50 percent of the time.”

But league teams are missing on 76 percent of their first-round quarterback picks, not counting the past two drafts, because the jury is still out on those quarterbacks.

“Now, with quarterbacks it’s much more difficult, and this year is a prime example of it,” Polian said. “As each year has gone by, quarterbacks come out earlier and earlier. They have less and less experience, and few of them meet the (Bill) Parcells test.”

Parcells, a former NFL coach who is a member of the Pro Football Hall of Fame, wanted his quarterback prospects to have played 30 collegiate games and have won at a 70-percent clip.

“If you apply the Parcells test, you’ll find that the guys who pass the Parcells test, succeed at a higher rate than those that don’t,” Polian said. “So, you’ve got to look into that and you have to apply it. Where should we take this guy? What are the odds of success? Have some solid criteria to go on.”

Ryan played in 43 games and made 40 starts at Boston College from 2004-07. He posted a 30-10 record (75 percent) as a starter. He passed the Parcells test.

Stafford starred at Georgia from 2006-08 and made 39 starts and was 30-9 (77 percent). He passed the Parcells test.

Of the top quarterbacks in the coming NFL draft, Polian correctly noted that only former Clemson quarterback Deshaun Watson passes the Parcells test.

“But the rest of them, it’s like the NBA — it’s one and dones,” Polian said. “(North Carolina quarterback Mitch) Trubisky is a true one-and-done.”

Some, quarterback-starved team will gamble on Trubisky.

“What are you going to do?” Polian said. “I don’t see any way of getting around it. You’re just taking a chance. You’re taking a chance on a guy with physical talent, but will he succeed? I don’t know?”

Dallas (Dak Prescott, fourth round), Seattle (Russell Wilson, third round), Cincinnati (Andy Dalton, second round) and Oakland (Derek Carr, second round) found quarterbacks outside of the first round.

One of Falcons general manager Thomas Dimitroff’s first tasks was to scout the quarterback class of 2008. He’s proud that the Ryan selection puts the Falcons in the 20 percent group.

“When we first looked at Matt back in 2008, I had the great opportunity to be around Tom Brady and see how he moved in the pocket and how he ad-libbed,” Dimitroff said. “Not necessarily from an athletic standpoint, but just his ability to be creative in the pocket. I thought Matt did an amazing job that way.”

Dimitroff also heavily scouted Chad Henne and Brian Brohm that year. Flacco, who played at Delaware after transferring from Pittsburgh, wasn’t high on the Falcons’ board.

Cleveland coach Hue Jackson has the No. 1 pick in the draft this season and for the second year in a row, appears set to pass on the top quarterback.

“Most importantly, obviously, guys have arm talent and can a guy process football at the rate that you need him to be able to do it,” Jackson said about evaluating quarterbacks. “Is he a guy who can lead an organization because I think we all know the quarterback becomes the face of the organization, I think that’s really important. A lot of pressure comes with that, so a guy’s got to be able to handle that.”

Minnesota general manager Rick Spielman selected Teddy Bridgewater 32nd in the first round in 2014. He also selected Ponder with the 12th pick in 2011.

“It’s very tough position to evaluate,” Spielman said. “You try to do everything you can and put all the tools in place and try to make the best decisions that you can. Christian Ponder did not work out. I take full responsibility for that.

“We were very excited about Teddy Bridgewater and his direction and his trajectory, where he was headed. He had a great offseason last year. he had a great training camp and preseason and then unfortunately you can’t predict what happened. I know Teddy is working extremely hard on getting back on the field as quickly as he can.”

Watson, a former Falcons ball boy from Gainesville, was 32-3 (91 percent) as a starter and clearly meets the Parcells test. But NFL scouts have questions about his accuracy and his ability to process NFL plays.

Former Tennessee quarterback Joshua Dobbs, of Alpharetta High, dazzled scouts with his arm strength at the combine. His accuracy is an issue, but he’s considered a third- or fourth-round developmental prospect, as Prescott was.

Dobbs meets part of the Parcells test. He started 35 games, but his record was 23-12 (66 percent).

“If you are going for a quarterback in this year’s draft, you have to have a really strong plan about what you’re going to do,” Dimitroff said. “How are you going to surround him? Do you have the talent around him? Have it really well thought out.”