Two-point conversion
In gridiron football, a two-point conversion or two-point convert is a play a team attempts instead of kicking a one-point conversion immediately after it scores a touchdown. In a two-point conversion attempt, the team that just scored must run a play from scrimmage close to the opponent's goal line and advance the ball across the goal line in the same manner as if they were scoring a touchdown. If the team succeeds, it earns two additional points on top of the six points for the touchdown, for a total of eight points. If the team fails, no additional points are scored. In either case, if any time remains in the half, the team proceeds to a kickoff.
Various sources estimate the success rate of a two-point conversion to be between 40% and 55%, significantly lower than that of the extra point, though if the higher value is to be believed, a higher expected value is achieved through the two-point conversion than the extra point.
Adoption of rule
The two-point conversion rule was instituted in college football in 1958, and in 1975 in Canadian amateur football and the Canadian Football League. In overtime in college football, two-point attempts are mandatory beginning with the third overtime, and in the CFL they are mandatory at any point in overtime.The American Football League used the two-point conversion during its ten-season existence from 1960 to 1969. After the NFL merged with the AFL, the rule did not immediately carry over to the merged league, though they experimented in 1968 with a compromise rule. The NFL adopted the two-point conversion rule in, 25 years after the merger. Tom Tupa scored the first two-point conversion in NFL history, running in a faked one-point attempt for the Cleveland Browns in a game against the Cincinnati Bengals in the first week of the 1994 season. He scored a total of three such conversions that season, earning him the nickname "Two-Point Tupa". That same season, the first two-point conversion in Super Bowl history came during Super Bowl XXIX when San Diego Charger Mark Seay caught a pass thrown by Stan Humphries.
The United States Football League adopted the two-point conversion rule for its entire existence 1983-85. The NFL's developmental league, NFL Europe, adopted the two-point conversion rule for its entire existence from 1991 through 2007.
Six-man football reverses the extra point and the two-point conversion: because there is no offensive line in that game variant, making kick protection more difficult, plays from scrimmage are worth one point but successful kicks are worth two. It is also reversed in many high school football and youth football leagues, since there are not often skilled kickers at that level. A variant of this, especially at the youth level, is to allow one point for a running conversion, two points for a passing conversion, and two points for a successful kick.
The Arena Football League has recognized the two-point conversion for its entire existence, allowing for either a play from scrimmage or a drop kick to be worth two points.
In 1968, leading up to the AFL–NFL merger, the leagues developed a radical "compromise" rule that would reconcile the fact that the NFL did not use the two-point conversion but the AFL did: the relatively easy one-point kick would be eliminated and only a play from scrimmage could score one point called a "pressure point". The rule was used for the interleague matchups for that preseason, and was not tried again. Both the World Football League and the XFL revived this concept, making it a point not to institute a two-point conversion rule so as to eliminate the easy kick. What would constitute a two-point conversion in other leagues counted only one point in the AFL–NFL games, WFL, or XFL. The WFL called it the "action point", used after touchdowns, which the WFL counted as seven points. However, the XFL later added a rule in the playoffs that allowed the scoring team to score two points by successfully executing a play from a point farther from the opponent's end zone.
During the summer of 2014, the conversion by place kick was under review by the NFL. This new format would award seven points for a touchdown without an extra point attempt, eight points with a successful conversion by running or passing, and six points with an unsuccessful attempt. This new format was proposed because of the almost certain probability of making a conversion by place kick. This proposal was never considered at the league owners' meeting in spring 2014; instead, the league used the first two weeks of its preseason for an experiment that moved one-point attempts back to the 20-yard line with the condition that if a team opted to attempt a two-point conversion instead, the line of scrimmage on the try would remain at the 2-yard line. The league adopted a slightly modified version of this rule starting with the 2015 season, with the line of scrimmage for one-point kick attempts at the 15-yard line instead of the 20; that same year, the CFL also moved back its line of scrimmage for one-point converts to the 25-yard line, thus making the length for a one-point attempt the same in both the NFL and CFL.
Defensive two-point conversion
In American college, professional, and Canadian football, a conversion attempt where the defense gains possession of the ball can be returned by the defense to the other end zone to give the defensive team two points. The team that scored the touchdown then kicks off as normal. This is rare because of the infrequent use of the two-point conversion and the rarity of blocked conversion kicks, combined with the difficulty of returning the ball the full length of the field. It has proven the winning margin in some games, the first such college game occurring September 10, 1988, when St. John's defeated Iona College, 26-24. Only once has a player scored two defensive two-point conversions in a game: Tony Holmes of the Texas Longhorns in a 1998 game against the Iowa State Cyclones on October 3.On May 19, 2015, the NFL owners adopted a proposal to permit a defensive two-point conversion for the season. On May 20, 2016, the owners adopted a proposal called the 2 point fair play rule. This prevents a defense from getting a turnover during a 2 point conversion and then purposely committing a "free" penalty to increase a chance at a 2 point return. If the defense is able to gain a takeaway and then commits a penalty, the opposing coach will have the option to accept the penalty and skip the kickoff. It has not yet been used in the NFL, but a similar rule has been used on two occasions in the CFL.
Stephone Anthony of the New Orleans Saints became the first NFL player to score a defensive two-point conversion, returning a blocked extra point kick from Graham Gano of the Carolina Panthers on December 6, 2015. On December 4,, Eric Berry of the Kansas City Chiefs became the first NFL player to return an interception for a defensive two-point conversion; it was thrown by quarterback Matt Ryan of the Atlanta Falcons.
The NCAA has allowed defensive two-point conversions in college football since the 1988 season. In that first season, there were 20 defensive conversions scored among all NCAA divisions, with two in Division I-A. The first defensive conversion in NCAA Division I-A was scored by Bill Stone of Rice University in a 54-11 loss to Notre Dame on November 5, 1988. The first college player to score a defensive two-point conversion was Rod Beauchamp of Colorado School of Mines on September 3, 1988, in a 36-2 loss to Hastings College, after the Hastings center snapped the ball over the holder's head. The first defensive conversion following a blocked extra point kick was scored by Springfield College in a 40-33 win over WPI on September 9, 1988.
High schools that follow the rules of the National Federation of State High School Associations do not allow defensive runbacks of recovered conversion attempts, and any recovery of the ball by the defense during the try is immediately blown dead and ruled as "no good."
Conversion safety
Rules in high school, college and professional football dictate that when a safety occurs during a two-point conversion or point-after kick, it is worth one point. It can be scored by the offense in college and professional football if the defense obtains possession of a live ball in the field of play, propels the ball into its own end zone, and the ball is then downed there with the defense in possession. This event has only occurred four times in NCAA Division I history. Before 2015, the only scenario in which a one-point safety could have been scored in the NFL would have involved, on a conversion attempt in which the ball was not kicked by the offense, the defense kicking or batting a loose ball out the back of the end zone without taking possession of it.A conversion safety can be earned by the defense if the offense retreated with the ball all the way back into its own end zone. Two potential scenarios include an errant snap or a fumble that is bobbled repeatedly until the offensive team recovers the ball in, or bats the ball through, its own end zone, and a defender attempting a defensive two-point conversion and fumbling the ball, with the offensive team recovering and establishing possession outside the end zone, then downing the ball in its own end zone. Although such a conversion safety has never been scored by the defense, this rule provides the only way in American professional football that a team could finish the game with a score of one point.. Following a 2019 rule change in college football, fifth and subsequent overtimes will involve teams attempting two point conversions rather than running plays from the 25-yard line. The rules regarding safeties on these plays are the same as for any other conversion attempt, opening up additional ways for a team to finish the game with exactly one point.
The high school football rulebook acknowledges the conversion safety, awarding one point for it, but also immediately ends a play if the opposing team gains possession of the ball, a rule similar to the one the NFL used before 2015. Thus, any situation that requires the defense to gain possession of the ball could not result in a conversion safety in games where that rulebook is used.
Choice of one- or two-point attempt
The coaches' choice of whether to attempt a one- or two-point conversion depends on the game's current score, the amount of time remaining, and their assessment of their team's chance of success.Analysis of historical data finds that the two-point conversion is successful about half the time, whereas one-point kicks are almost always successful. Therefore the expected value of both options is roughly similar, with the critical factor being whether the chance of a successful two-point conversion is more or less than half that of a successful kick. However, the mathematics regarding maximizing a team's chances of winning are more complicated. For example, late in a game, a team that is one point up after a touchdown would gain little benefit from a one-point attempt, because regardless of success, the team would still lose if the opposition later scored a field goal. In such a situation, the two-point conversion would be the better option. If successful, an opposition field goal would then only tie the game.
A more complicated scenario is when a team is trailing by 14 points. The team could choose to go for two, because, if successful, the team could then kick an extra point following the next score to secure a win. On the other hand, if the two-point conversion fails, the team still has a chance to succeed on the next two-point conversion to get to fourteen. Mathematically, therefore, the minimum probability of converting a two-point try either on the first attempt or the second must be higher than the maximum probability of missing both. This occurs when the probability of missing both is 0.618 × 0.618, or 38.2%. As long as the probability of converting any individual two-point attempt is higher than 38.2% percent, it is optimal to adopt this strategy. Notably, Texas Longhorns coach Darrell Royal successfully used this strategy to defeat Arkansas in 1969's Game of the Century.
An analysis can be done for all situations, resulting in a table that can be consulted when a decision is needed. A chart made by UCLA offensive coordinator Dick Vermeil in the early 1970s is one of the most well-known.
In practice, two-point conversion attempts are rare, being done only after less than 1-in-10 touchdowns in the NFL. This proportion rose after the one-point kick was moved back to the 15-yard line, increasing the difficulty of scoring the single extra point.