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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 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. If the team fails, no additional points are scored. In either case, 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 has been used in college football since 1958 and more recently in Canadian amateur football and the Canadian Football League (1975). In overtime situations in college football, the two-point conversion is the mandatory method of scoring after a touchdown beginning with the third overtime.
The American Football League used the two-point conversion during its ten seasons 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. 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".
Six-man football reverses the extra point and the two-point conversion: because there is no offensive line in that league, 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 (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. 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. 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).
As of the summer of 2014, the conversion by place kick is 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 extra point attempt. This new format is proposed because of the almost certain probability of making a conversion by place kick (1,260 out of 1,265 for the 2013 season). 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.
Defensive two-point conversion
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 two-point conversion attempt or a blocked PAT 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 extra points, 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 an individual 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.
College football has allowed for defensive two-point conversions since 1988.
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 a two-point attempt resulting in recovery of the ball by the defense is immediately blown dead and ruled merely as 'no good'.
NCAA rules 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 ball if the defense has 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. In principle, in college or pro ball 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, although this possibility is only hypothetical and has yet to ever occur. If it occurred, it would provide the only way in which a team could finish the game with only a single point (with the exception that Canadian football allows another one-point play called the single or rouge).
Mathematical analysis of the two-point conversion
In 2007, blogger Eric Menhart analyzed the value of going for a two-point conversion compared to a field goal style extra point in the National Football League, concluding that teams are better served kicking the extra point in most cases. This was consistent with the results in the XFL, which had an average success rate of 40% for their one-point conversions (the XFL, as previously mentioned, required scrimmage plays for one point and did not allow kicks). This counters Tuesday Morning Quarterback columnist Gregg Easterbrook's theory that since the average yards gained on a typical scrimmage play is 5 yards, that the opposite is true and that the two-point conversion would, on average, bring a greater point value return; furthermore, Easterbrook cites the Football Prospectus, which says that the average success rate on a two-point conversion is between 50% and 55%, depending on the time frame used and the situations in which the conversion is attempted. The two-point conversion usually involves goal-line defenses and are thus not typical scrimmage plays, resulting in shorter average gains. Regardless of the actual success rate, professional teams seldom attempt the two-point conversion, unless an "eight-point" touchdown results in a certain point margin, either leading, tied, or behind, preferring the near-certain single point (see below.)
There is a relatively common game situation in which the two-point conversion can be an optimal strategy even if its likelihood is under 50%. A team down fourteen points in the final minutes must score two touchdowns while keeping its opponents scoreless in order to tie or win the game. In this situation, a team could choose to go for two after the first score, because if successful, the team could then kick an extra point in following the next score to secure a win, while if it fails, the team still has a chance to make the next two-point conversion to get to fourteen. Though the logic seems counter-intuitive, this maximizes a team's win probability. The odds of converting a two-point try either on the first attempt (securing a win) or the second (securing a tie and sending the game into overtime) are higher(38.2%) than the odds of missing both (securing a loss), (38.19%).(The odds of missing both is calculated as .618 x .618 = .3819 or 38.19%) The .618 in each case of failure to convert is derived from (1- probability of converting the 2 point try) or (1-.382) which = .618 So as long as the expected probability is higher than 38.2 % percent it is optimal to adopt the above strategy. Notably, Texas Longhorns coach Darrell Royal successfully used this strategy to defeat Arkansas in 1969's Game of the Century.
Two-point conversion chart
This version of the two-point conversion chart was first developed by Dick Vermeil in the early 1970s when he was offensive coordinator under Tommy Prothro at UCLA. The chart is still used by coaches in helping them to determine whether to go for a two-point or one-point conversion after a touchdown in various situations. The score margin listed in the chart is the margin after the touchdown is scored, but before the conversion is attempted. If you examine the chart you will see that this optimal strategy detailed above contradicts the chart when a team is trailing by 8 points after a touchdown is scored but before the decision is made for extra points. Thus the chart is only valid if the success rate of 2 point tries is less than 38.2%. All NFL studies have indicated (between 1994 and 2012 the success rate was 44.79%) that it is higher therefore Vermeil's chart is wrong and the NFL coaches should adjust their strategy. In the Canadian Football League it has even been as high as 72% success rate. With the 2015 NFL rule change that forces the offence to line up at the 15 yard line to kick the extra point and the 2 yard line to try for 2 points( no change to the rule) and with the ball being a live ball (defence can force a safety if they return the ball to the opposite end zone) if blocked or fumbled, then this chart might have to be revised because of the different expectation of success of each decision after scoring a touchdown.
|Lead By||Trail By|
|1 Point||Go For 2||1 Point||Go For 1|
|2 Points||Go For 1||2 Points||Go For 2|
|3 Points||Go For 1||3 Points||Go For 1|
|4 Points||Go For 2||4 Points||Go For 1|
|5 Points||Go For 2||5 Points||Go For 2|
|6 Points||Go For 1||6 Points||Go For 1|
|7 Points||Go For 1||7 Points||Go For 1|
|8 Points||Go For 1||8 Points||Go For 1|
|9 Points||Go For 1||9 Points||Go For 2|
|10 Points||Go For 1||10 Points||Go For 2|
|11 Points||Go For 1||11 Points||Go For 1|
|12 Points||Go For 2||12 Points||Go For 2|
|13 Points||Go For 1||13 Points||Go For 1|
|14 Points||Go For 1||14 Points||Go For 1|
|15 Points||Go For 2||15 Points||Go For 1|
|16 Points||Go For 1||16 Points||Go For 2|
|17 Points||Go For 1||17 Points||Go For 1|
|18 Points||Go For 1||18 Points||Go For 1|
|19 Points||Go For 2||19 Points||Go For 2|
|20 Points||Go For 1||20 Points||Go For 1|
- Time "The Two-Point Conversion,", October 6, 1958.
- "CFL History 1970s". Canadian Football League. Retrieved 18 January 2013.
- WiseGeek.com  Definition.
- "NFL Will examine eliminating the extra point". NBC Sports. Retrieved 31 January 2014.
- "NFL to change extra-point kicks to longer distance". Yahoo! Sports. Retrieved 19 May 2015.
- Victor Mather (September 10, 2015). "N.F.L. Team Scoring Just 1 Point? Now It’s Possible". New York Times.
- EricMenhart.com "Going For Two in the NFL: Right or Wrong?,", June 28, 2007.
- Two Point Conversion Chart
- http://www.usatoday.com/sports/football/nfl/2006-11-07-four-downs_x.htm?POE=SPOISVA Four downs: Parcells deals with second-guessing]