Two-point conversion

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Navy quarterback Kaipo-Noa Kaheaku-Enhada puts the ball over the goal line for a two-point conversion against the Utah Utes, 2007

In American and Canadian 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 (5-yard line in amateur Canadian, 3-yard line in professional Canadian, 3-yard line in amateur American, 2-yard line in professional American) 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.[1][2]

Adoption of rule[edit]

The two-point conversion rule has been used in college football since 1958,[3][4][5] and more recently in Canadian amateur football and the Canadian Football League (1975).[6] In overtime situations in college football, the two-point conversion is the mandatory method of scoring after a touchdown beginning with the third overtime, and in the CFL it is mandatory at any point in overtime.

The American Football League (AFL) 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 (see below). The NFL adopted the two-point conversion rule in 1994.[7][8] Tom Tupa scored the first two-point conversion in NFL history, running in a faked extra 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 successful 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 NFL's developmental league, NFL Europe (and its former entity, the World League of American Football), 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.[citation needed] 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 (in both its original 1987–2008 incarnation and its ongoing revival), allowing for either a play from scrimmage or a drop kick to be worth two points. (The additional extra point for a drop kick is unique to arena football.)

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 recognize the two-point conversion but the AFL did: the relatively easy extra point kick would be eliminated and only a play from scrimmage would score one point called a "Pressure Point". The rule would be used for the interleague matchups for that preseason, and would not be 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 only counted 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 (or even three) points by successfully executing a play from a point farther from the opponent's end zone (two points if the team could score from the five-yard line and three points if they could score from the ten-yard line).

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 (1,260 out of 1,265 for the 2013 season).[9] 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 extra 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 extra-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 converts to the 25-yard line (while moving the scrimmage line for a two-point convert ahead two yards to the 3-yard line), thus making the length for an extra-point attempt the same length in both the NFL and CFL (taking into account the NFL positioning their goalposts on the end line, and the CFL's on the goal line).

Defensive two-point conversion[edit]

In American college, professional, and Canadian football (as well as, for a significant period of time, the Arena Football League, where missed extra points are rebounded back into the field of play), 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. Only once has a player scored two defensive two-point conversions in a game: Tony Holmes of the Texas Longhorns in a 1998 Big 12 Conference 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 2015 season.[10][11]

Stephone Anthony of the New Orleans Saints became the first NFL player to score a defensive two-point conversion; he returned a blocked extra point kick from Graham Gano of the Carolina Panthers on December 6, 2015.[12]

On December 4, 2016, 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.[13]

The NCAA has allowed defensive two-point conversions in college football since the 1988 season.

High schools that follow the rules of the National Federation of State High School Associations (all U.S. high schools except those in Texas and Massachusetts, which use NCAA rules instead) 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 merely as "no good."

Conversion safety[edit]

Rules in high school, college and professional football dictate that when a safety occurs during a two-point conversion or point-after kick (officially known in the rulebooks as a try), it is worth one point. It can be scored by the offense in college and professional football (following an NFL rule change in 2015) if the defense obtains possession of a live ball in the field of play, propels the ball (by carrying it or fumbling it) into its own end zone, and then is downed there with the defense in possession of the ball. This event has only occurred twice 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 the defense kicking or batting a loose ball out the back of the end zone without taking possession of it.[14]

A conversion safety could be earned by the defense if the offense retreated with the ball all the way back into its own end zone; most plausibly this would involve a fumble at some point during the play. 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 (similar situations have been documented in regular play from scrimmage[15] and are more likely in arena football with its much shorter, narrower and bounded field of play), or, in the college and professional game, a defender attempting a defensive two-point conversion, fumbling the ball and having the offensive team recover in their own end zone. Although such a conversion safety has never been scored by the defense, this rule provides the only way in American football that a team could finish the game with a score of one point. (Canadian football allows another one-point play called the single or rouge).[16]

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[edit]

Coaches' choices of whether to attempt a one- or two-conversions will depend on a number of factors: the game's current scoreline, the amount of time remaining, and their assessment of their team's chances of success.[17]

Analysis of historical data finds that the two-point conversion is successful about half the time, whereas one-point kicks are almost always successful. As such, 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.[17][18] 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, as, regardless of success, the team would still lose if the opposition scored a late field goal. In such a situation, the two-point conversion would be the better option, as this would mean — if successful — an opposition field goal would only tie the game.[17]

A more complicated scenario is when a team is trailing by eight 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 (securing a win) or the second (securing a tie in regulation time) must be higher than the maximum probability of missing both (securing a loss). This occurs when the probability of missing both is 0.618 × 0.618, or 38.2%.[19] 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.[20][21] 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.[17] A chart made by UCLA offensive coordinator Dick Vermeil in the early 1970s is one of the most well-known.[22][23]

In practice, two-point conversion attempts are rare, being done only after less than 1-in-10 touchdowns in the NFL.[18] 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.[18]

Arena and other indoor football[edit]

In indoor versions of the sport, a two-point conversion is scored after a touchdown in the manner described above; that is, by running a play from scrimmage from the two-yard line in which the ball carrier succeeds in crossing the goal line while in possession of the ball, or the receiver makes a valid reception in the end zone or crosses the goal line in possession of the ball after having caught it in the field of play. In Arena football only, a successful drop kicked conversion also counts as a two-point conversion.

References[edit]

  1. ^ 412sportsanalytics "Two-Point Conversion: My two-data-cents,", 2016.
  2. ^ K. Pelechrinis "Decision Making in American Football: Evidence from 7 Years of NFL Data, in Machine Learning and Data Mining for Sports Analytics", 2016.
  3. ^ "WSC coach Sutherland favors new rule on point-after scores". Spokane Daily Chronicle. (Washington). January 13, 1958. p. 17.
  4. ^ Fullerton, Hugh, Jr. (December 18, 1958). "Two-point conversion rule gets approval in AP poll". Ludington Daily News. (Michigan). Associated Press. p. 10.
  5. ^ "The Two-Point Conversion". Time. 1958-10-06. Archived from the original on 2009-02-06.
  6. ^ "CFL History 1970s". Canadian Football League. Archived from the original on 2013-03-16. Retrieved 2016-08-02.
  7. ^ Goldberg, Dave (March 23, 1994). "Owners OK two-point conversion". Gadsden Times. (Alabama). Associated Press. p. D1.
  8. ^ WiseGeek.com [1] Definition.
  9. ^ "NFL Will examine eliminating the extra point". NBC Sports. Retrieved 31 January 2014.
  10. ^ Patra, Kevin (May 19, 2015). "NFL moves extra point to 15-yard line for 2015 season". National Football League. Retrieved December 7, 2015.
  11. ^ Wilner, Barry (May 19, 2015). "NFL to change extra-point kicks to longer distance". Yahoo! Sports. Associated Press. Retrieved December 7, 2015.
  12. ^ Dubin, Jared (6 December 2015). "Saints first-ever team to run back a blocked extra point for two points". CBS Sports. Retrieved 7 December 2015.
  13. ^ Teicher, Adam (December 4, 2016). "Eric Berry has pick 6, 'pick 2' in emotional homecoming victory". ESPN. Retrieved December 4, 2016.
  14. ^ Bialik, Carl (January 3, 2013). "In Praise of the One-Point Safety". The Wall Street Journal. Retrieved March 9, 2013.
  15. ^ "WATCH: Louisiana Tech loses 87 yards on one play in the most comical fashion". cbssports.com.
  16. ^ Victor Mather (September 10, 2015). "N.F.L. Team Scoring Just 1 Point? Now It's Possible". New York Times.
  17. ^ a b c d Morris, Benjamin (2017-02-03). "When To Go For 2, For Real". FiveThirtyEight. Retrieved 2018-09-12.
  18. ^ a b c Stuart, Chase (2016-11-15). "More NFL Teams Are Going For Two — Just As They Should Be". FiveThirtyEight. Retrieved 2018-09-12.
  19. ^ The probability of failure to convert is "1 minus the probability of converting the two-point try", (1 − 0.382), or 0.618.
  20. ^ "Down Late in the Game? Go for Two". wordpress.com. 18 April 2013.
  21. ^ "The Game Designer: Go For Two!". thegamedesigner.blogspot.com. 16 January 2011.
  22. ^ "Two Point Conversion Chart". theredzone.org.
  23. ^ "Four downs: Parcells deals with second-guessing - USATODAY.com". www.usatoday.com.