How NFL Review Rules Work

Review rules are now here to stay. Most agree that they have helped make the game fairer. But no matter how efficient the technology, replays will never eliminate all controversies.
Review rules are now here to stay. Most agree that they have helped make the game fairer. But no matter how efficient the technology, replays will never eliminate all controversies.

The final seconds of the game -- the quarterback throws to the end zone: touchdown! No, the official is ruling the receiver was out of bounds. Now comes the agonizing wait while the play is reviewed.

This scenario has become a common feature of NFL football. It's made possible by the review rules, also known as the instant replay rules. The rules give the officials on the field another set of eyes to get calls right. With high definition and super slo-mo, those eyes are often much keener than those of any official or fan.


Review rules have sometimes generated controversy. Some fans and team owners prefer to keep the human factor in the game. Officiating errors are part of the history and lore of the league, they argued. Others felt that reviews slowed the game too much, especially for fans sitting in Buffalo's icy Ralph Wilson Stadium in December.

The rules have their origin in the invention of television instant replay, which was first used in the broadcast of the 1963 Army-Navy football game [source: Starkey]. Once fans at home had access to replays, bad calls by the officials became embarrassingly obvious. The league was pressured to use the replay tool to get them right.

But the first review rules didn't come into effect until 1986. They put the decision to review under the complete control of a video-review official in the booth. Many thought the system was arbitrary and took too much time. It was abandoned in 1992 [source: Long].

After several disputed calls during the 1998 season, revised review rules returned in 1999. The new rules gave coaches the power to call for a review for most of game. They assigned the referee, not an assistant in the booth, the duty of making the decision. These rules were renewed with minor revisions until 2007, when the league made them permanent [source: Associated Press].

But not all plays are reviewable. Read on to find out which are, and which are not.

Reviewable Plays in the NFL

If an offensive guard puts his hands on an onrushing tackle, the official uses his judgment to decide whether the contact is holding. The call is not reviewable. If a pass receiver lands with only one foot in bounds, it's clear to anyone that the pass should not count as completed. There, a review can clearly expose whether an official was correct.

NFL rules are complicated, and they're frequently tweaked and revised. Basically, there are three types of reviewable plays:


  1. Calls involving sidelines, goal lines and end line. This includes whether a runner broke the plane of the goal line, whether a player stepped out of bounds, whether a player recovered a loose ball in or out of bounds, or whether a loose ball hit the sideline
  2. Calls involving passes. When the ball was knocked loose, was the player passing or was it a fumble? Was a pass completed or intercepted? Did an ineligible player touch a forward pass? Did a player cross the line of scrimmage before passing?
  3. Other detectable issues. Was a runner down by contact prior to fumbling? Were there more than 11 players on the field at the snap? Was the ball spotted correctly when a first down was at stake? Was a kick that passed the goalpost lower than the uprights successful?

[sources: Sando, Oldfather].

The review rules specify a number of situations that are not reviewable. These include:

  • All judgment calls, such as pass interference, holding and roughing the passer
  • A play where a runner is ruled down by defensive contact, not involving a fumble
  • The recovery of a loose ball in the field of play
  • Inadvertent whistles and down calls

Time on the clock can only be reviewed at the very end of a half. Kick attempts can't be reviewed if they sail higher than the uprights.

Some reviews have not only changed games but helped change what's reviewable. During the final seconds of a Browns-Ravens game in November 2007, Cleveland kicker Phil Dawson booted a 51-yard field goal. The ball hit an upright, ricocheted off the goal-post gooseneck and sailed back toward the field. The officials first ruled the kick no good, but the replay clearly showed the ball had gone through the goal. At the time, field goals were not reviewable, but the referee reversed the call anyway (he claimed the replay wasn't a factor). The Browns tied the game and won in overtime. Later, a new rule was added -- known as the Phil Dawson Rule -- and certain field goals are now reviewable [source: DeTullio]

For most of the game, a coach's challenge is needed to start the review process. Read on to find out how this works.

NFL Coach's Challenge

At any time before the two-minute warning of each half or overtime period, the head coach of either team can signal a challenge by throwing a red flag onto the field. He's allowed only two challenges per game, but if both challenges are successful, he's given a third. He must issue his challenge before the next snap of the ball.

If the coach's challenge is successful -- that is, the ruling on the field is overturned -- then his team isn't charged with a timeout. If it's unsuccessful, it costs the team a timeout. A coach can't challenge any ruling if he doesn't have at least one timeout remaining.


The coach must consider his options carefully. Should he save a timeout so that he keeps the option to challenge? Should he risk a timeout on a challenge that may not be successful?

He must also decide quickly. He usually hasn't seen the play clearly from the sidelines. He may receive advice from an assistant coach in the booth who's watching the network television feed. Or he may heed his players who were close to the action. Knowing that the time to decide is limited, an offensive team receiving a favorable call might snap ball quickly to close off the possibility of a review.

Once the coach issues his challenge, the referee goes to one of two or three shielded television monitors near the field. He looks at the play from all relevant angles that are available. He has 60 seconds to review the images; then he must make a decision.

  • He may overrule and change the call on the field. In this case, he might make other revisions, such as resetting the clock.
  • He may confirm the original call, meaning that on replay he sees the call was correct.
  • He may rule that the original call stands, meaning he did not see enough visual evidence on replay to either confirm or overturn the call on the field.

During the 2009 season, there were 328 challenges -- 228 by coaches and 100 by replay assistants. A total of 126 challenges resulted in reversals. During the playoffs, 15 reviews were called for, with six reversals. Reversal rates have increased over time. In 1999, only 29 percent of challenges were successful, compared to 40 percent in 2009 [source: Myers].

The replay assistant in the booth often has to make some of the most crucial review decisions. Read on to find out how those rules work.

NFL Booth Review

After the two-minute warning, the responsibility of calling reviews shifts from coaches to the replay assistant in the booth. Sometimes those decisions can directly determine the outcome of the game. The replay assistant only has the time between plays to decide whether to order review. Even if a call is not overturned, a decision to review can affect a team's momentum at a critical juncture.

The replay assistant is part of the officiating team. He participates in the review process throughout the game, but can't initiate a review until the two-minute warning has passed. If he then sees a call that appears questionable on replay, he activates a vibrating buzzer worn by the referee.


To make a speedy review possible, high-definition signals from all cameras are sent by fiber optic cables to the replay booth. There they are recorded on two computer servers and cued up by a technician. A video operator transfers relevant replays to a monitor, which the replay assistant looks at to decide whether a review is called for. A communicator watches the action on field, announcing to the replay assistant whether play has resumed [source:].

If the assistant calls for a review, the replay signal seen by the referee is sent to the two shielded monitors on the sidelines. In outdoor stadiums, a third is placed in a runway in case of bad weather.

Review rules are now here to stay. Most agree that they have helped make the game fairer. But no matter how efficient the technology, replays will never eliminate all controversies.

For example, during a November 1989 Packers-Lions game, Green Bay quarterback Don "Magic" Majkowski threw an apparent touchdown to win 14-13. But field officials ruled that he had stepped over the line of scrimmage before throwing: no touchdown. Review by the assistant in the booth overruled the call and awarded the touchdown. It became known as "Instant Replay Game." Because the truth was in the eye of the beholder, fans have argued the call ever since [source: Sorgi].

Read on for more information about NFL review rules.

Lots More Information

Related HowStuffWorks Articles


  • Anderson, Dave. "Just Thank Testaverde For Replay." New York Times, March 18, 1999. (Sept. 23, 2010)
  • Associated Press. "NFL owners vote to make replay permanent." March 27, 2007. (Sept. 23, 2010)
  • Berman, Mitchell. "After Further Review," Slate, Dec. 22, 2009. (Sept. 23, 2010)
  • DeTullio, Brian. "Phil Dawson No-Shows Cleveland Browns OTAs." Bleacher Report, May 18, 2010. (Sept. 23, 2010)
  • Long, Tony. "March 11, 1986: NFL Adopts Instant Replay." Wired, March 11, 2009. (Sept. 23, 2010)
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