NFL Playoffs

The National Football League (NFL) playoffs are a single-elimination tournament held at the end of the 16-game regular season to determine the NFL champion. Six teams from each of the league's two conferences qualify for the playoffs based on regular season records, and a tie-breaking procedure exists in the case of equal records. It ends with the Super Bowl, the league's championship game, which matches the two conference champions. NFL post-season history can be traced to the first NFL Championship Game in 1933, though in the early years, qualification for the game was based solely on regular season records. The first true NFL playoff began in 1967, when four teams qualified for the tournament. When the league merged with the American Football League in 1970, the playoffs expanded to eight teams. The playoffs were expanded to ten teams in 1978 and twelve teams in 1990. The NFL is the only one out of the four major professional sports leagues in the United States to use a single-elimination tournament in its playoffs, the National Basketball Association and the National Hockey League all use a "best-of" format instead. Currently, the Houston Texans, who joined the league as an expansion team in 2002, are the only NFL franchise that has never qualified for the playoffs.

Current playoff system
The 32-team league is divided into two conferences: the American Football Conference (AFC) and the National Football Conference (NFC), each of which has 16 teams. Since 2002, each conference has been further divided into 4 divisions of 4 teams each. The tournament brackets are made up of six teams from each of the league's two conferences, following the end of the 16-game regular season. Qualification into the playoffs works as follows:
 * The 4 division champions from each conference (the team in each division with the best record), which are seeded 1 through 4 based on their overall won-lost-tied record.
 * Two wild card qualifiers from each conference (the non division-champions with the conference's best winning percentages), which are seeded 5 and 6.

The first round of the playoffs is dubbed the Wild Card Playoffs (or Wild Card Weekend). In this round, the third-seeded division winner hosts the sixth seed wild card, and the fourth seed hosts the fifth. There are no restrictions regarding teams from the same division matching up in any round. The 1 and 2 seeds from each conference receive a bye in the first round, which entitles these teams to automatic advancement to the second round, the Divisional Playoffs, where they face the Wild Card Weekend survivors. The NFL does not use a fixed bracket playoff system. The number 1 seed will host the lowest surviving seed from the first round (seed 4, 5 or 6), while the number 2 seed will play the other team (seed 3, 4 or 5). The two surviving teams from each conference's Divisional Playoff games then meet in the respective AFC and NFC Conference Championship games, with the winners of those contests going on to face one another in the Super Bowl. Only twice since 1990 has neither a number one-seeded team nor a number two-seeded team hosted a conference championship game (in the 2006 AFC Championship the #3 seeded Indianapolis Colts hosted the #4 seeded New England Patriots with the Colts winning 38-34 and the 2008 NFC Championship the #4 seeded Arizona Cardinals hosting the #6 seeded Philadelphia Eagles with the Cardinals winning 32-25). If teams are tied (having the same regular season won-lost-tied record), the playoff seeding is determined by a set of tie-breaking rules. One potential disadvantage is that the two teams with the best records in a conference could play each other before the conference championship if they are in the same division. The better team would be seeded #1, while the lesser team would be seeded #5 as the top wild card team, and as shown in the diagram, it is possible for the #1 division winner to play the top wild card team in the divisional round. (See also the "Modification proposals" section below).

Breaking ties
Often, teams will finish a season with identical records. It becomes necessary, therefore, to devise means to break these ties, either to determine which teams will qualify for the playoffs, or to determine seeding in the playoff tournament. The rules below are applied in order until the tie is broken. If three teams are tied for one playoff spot and the third team is eliminated at any step, the tie breaker reverts to step one for the remaining two teams. If multiple playoff spots are at stake, the rules are applied in order until the first team qualifies, then the process is started again for the remaining teams. The tie-breaking rules have changed over the years, with the most changes being made in 2002 to accommodate the league's realignment into eight four-team divisions; record vs. common opponents and most of the other criteria involving wins and losses were moved up higher in the tie-breaking list, while those involving compiled stats such as points for and against were moved to the bottom. The current tiebreakers are as follows:

Playoff and championship history
The NFL's method for determining its champions has changed over the years.
 * For playoff games of the American Football League prior to the AFL-NFL merger, see AFL playoffs.

Early years
From the league's founding in 1920 until 1932, there was no scheduled championship game. From 1920–1923, the championship was awarded to a team by a vote of team owners at the annual owners' meeting. From 1924–1932, the team having the best winning percentage was awarded the championship. As each team played a different number of games, simply counting wins and losses would have been insufficient. Additionally, tie games were not counted in the standings in figuring winning percentage (under modern rules, ties count as ½ win and ½ loss).

1932 playoff game
In 1932, the Chicago Bears (6–1–6) and the Portsmouth Spartans (6–1–4) were tied at the end of the season with the identical winning percentage of .857 (The Green Bay Packers (10–3–1) had more wins, but a lower winning percentage (.769) as calculated under the rules of the day, which omitted ties). An additional game was therefore needed to determine a champion. It was agreed that the game would be played in Chicago at Wrigley Field, but severe winter weather and fear of a low turnout forced the game to be moved indoors to Chicago Stadium. The game was played under modified rules on a shortened 80-yard dirt field, and the Bears won with a final score of 9–0. As a result of the game, the Bears had the better winning percentage (.875) and won the league title. The loss gave the Spartans a final winning percentage of .750, and moved them to third place behind the Packers. While there is no consensus that this game was a real "championship" game (or even a playoff game), it generated considerable interest and led to the creation of the official NFL Championship Game in 1933.

Before the Super Bowl
Given the interest of the impromptu "championship game", and the desire of the league to create a more equitable means of determining a champion, the league divided into two conferences beginning in 1933. There was no tie-breaker system in place, any ties in the final standings of either conference resulted in a playoff game being played at 1941, 1943, 1947, two games in 1950, one in 1952, 1957, 1958, and 1965. Since the venue and date of the championship game were often not known until the last game of the season had been played, these playoff games sometimes resulted in delaying the end of the season by one week. The playoff structure used from 1933 to 1966 was considered inequitable by some because of the number of times it failed to match the teams with the two best records in the championship game. Four times between 1950 and 1966 (in 1951, 1956, 1960, and 1963) the team with the second-best win-loss record did not qualify for the playoffs while the team with the third-best record advanced to the championship game. For the 1967 NFL season, the NFL expanded to 16 teams, and split its two conferences into two divisions each, with four teams in each division. The four division champions would advance to the NFL playoffs, and to remain on schedule, a tie-breaker system was introduced. The first round of playoffs determined the conference's champion and its representative in the NFL Championship Game, played the following week. Thus, 1967 was the first season there was a scheduled playoff tournament to determine the teams to play for the NFL Championship. During the three years (1967-69) that this playoff structure was in effect, there was one use of the tie-breaker system. In 1967 the Los Angeles Rams and Baltimore Colts ended the season tied at 11-1-2 for the lead in the Coastal Division. The Colts came into the last game of the season undefeated, but were beaten by the Rams. Though the Colts shared the best won/loss record in the NFL that year, they failed to advance to the playoffs while three other teams with worse records won their divisions. This event figured into the decision in 1970 to include a "wildcard" team in the playoff tournament. During the 1960s, a third-place playoff game was played in Miami, called the Playoff Bowl. It was contested in early January following the 1960–69 seasons. Though official playoff games at the time they were played, the NFL now officially classifies these ten games (and statistics) as exhibitions, not as playoff games.

AFL playoffs
Since it would eventually merge with the NFL, the history of the AFL's playoff system merits some explanation. For the 1960–68 seasons, the AFL used the two-divisional format identical to the NFL to determine its champion. There was no tie-breaker system in place, so ties atop the Eastern Division final standings in 1963 and Western Division in 1968 necessitated playoff games to determine each division's representative in the championship. For the 1969 season, a first round was added whereby the each division winner played the second place team from the other division. The winners of these games met in the AFL Championship Game. In the only year of this format, the AFL Champion Kansas City Chiefs were actually the second place team in the Western division. The Chiefs would go on to win Super Bowl IV that season, thus becoming the first non-division winner to win a Super Bowl.

Super Bowl and merger
The Super Bowl began as an inter-league championship game between the AFL and NFL, an idea first proposed by Kansas City Chiefs owner Lamar Hunt. This compromise was the result of pressures the upstart AFL was placing on the older NFL. The success of the rival league would eventually lead to a full merger of the two leagues. From the 1966 season to the 1969 season (Super Bowls I–IV) the game featured the champions of the AFL and NFL. Since the 1970 season, the game has featured the winners of the National Football Conference (NFC) and the American Football Conference (AFC). When the leagues merged in 1970, the new NFL (with 26 teams) reorganized into two conferences of three divisions each. From the 1970 season to the 1977 season, four teams from each conference (for a total of eight teams) qualified for the playoffs each year. These four teams included the three division champions, and a fourth Wild Card team. Originally, the home teams in the playoffs were decided based on a yearly rotation. From 1970 to 1974, the divisional playoff round rotated which of the three division champions would not have home field advantage, with the wild card teams and the teams they would face in the divisional playoff game would never have home field advantage through out the playoffs. Starting in 1970, the divisional playoff games consisted of the AFC Central champions and the NFC West champions playing there games on the road. Then in 1971 it rotated to the AFC East champions and the NFC East champions playing their games on the road. In the 1972 divisional playoff games, the AFC West champions and the NFC Central champions were the visiting teams. And 1973 it would start all over with the AFC Central and NFC West again, and so on. If the "road" division winners advanced to the conference championship games they would be visiting teams again, unless they played a wild card winner. The league did not institute a seeding system for the playoffs until 1975, where the surviving clubs with the higher seeds were made the home teams for each playoff round. Thus, the top seeded division winner played the wild card team, and the remaining two division winners played at the home stadium of the better seed. However, two teams from the same division could not meet prior to the conference championship game. Thus, there would be times when the pairing in the Divisional Playoff Round would be the 1 seed vs. the 3 seed and 2 vs. 4.

Expansion
Following an expansion of the regular season from 14 to 16 games in the 1978 season, the league added one more wild card team for each conference. The two wild card teams played the week before the division winners. The winner of this game played the top seeded division winner as was done from 1970–1977. The league continued to prohibit intra-divisional games in the Divisional Playoffs, but allowed such contests in the Wild Card Round. This ten-team playoff format was used through the 1989 season. Under this system, the Oakland Raiders became the first Wild Card team to win a Super Bowl following the 1980 season. During the strike-shortened 1982 season, only nine regular season games were played, and a modified playoff format was instituted. Divisional play was ignored (there were some cases where division rivals had both games wiped out by the strike, although each division ultimately sent at least one team to the playoffs), and the top eight teams from each conference (based on W-L-T record) were advanced to the playoffs. As a result, this became the first time that teams with losing records qualified for the playoffs: the 4-5 Cleveland Browns and the 4-5 Detroit Lions. Several times between 1978-89, the two Wild Card games had to be played on different days. Normally they both would be held on Sunday. In 1983 and 1988, the games were split between Saturday and Monday because Sunday was Christmas, and the NFL had avoided playing on that day at the time. In 1984, both games were played in the Pacific Time Zone, so they had to be played on Saturday and Sunday to accommodate for time differences. In 1985, both the New York Giants and Jets hosted Wild Card games. As they have shared a home stadium since 1984, the games had to be played on different days. For the 1990 season, a third wild card team for each conference was added, expanding the playoffs to twelve teams. The lowest-seeded division winner was then "demoted" to the wild card week. Also, the restrictions on intra-divisional games during the Divisional Playoffs were removed. The 1990 format continued until the 2002 expansion and reorganization into eight divisions. In this current format, as explained above, the 4 division winners and 2 wild cards are seeded 1–6, with the top 2 seeds receiving byes, and the highest seed in each round guaranteed to play the lowest seed. Also, seeds determine the home-field advantage.

Modification proposals
Since the 2002 changes, several division champions have hosted wild card playoff teams that had a better win-loss record. Also, there have been division champions that have had worse records than teams failing to qualify for the playoffs. In one notorious example, 2008 saw the San Diego Chargers clinch the AFC West championship with only an 8-8 record, and thus host the 12-4 Indianapolis Colts in the Wild Card Round, while the New England Patriots failed to even secure a wild card spot at 11-5. The Chargers then went on to defeat the Colts in that playoff game. As a result, frequent calls have been made to modify the playoff format even further. One proposal has been to expand the playoffs to 14 teams. Proponents of expansion note the increased revenue that could be gained from an additional two playoff games. They also note that the 12-team playoff system was implemented when the league only had 28 teams and six divisions (of 4 to 5 teams each). The opposition to such a move notes that an expansion of the playoffs would "water down" the field by giving access to lower-caliber teams. Opponents to expansion further point to the NBA Playoffs and the NHL playoffs where 16 of 30 teams qualify for the post season, and there is often a decreased emphasis on regular season performance as a result. After the 2007 playoffs saw two wild card teams with better records (Jacksonville Jaguars and eventual Super Bowl XLII champions New York Giants) go on the road to defeat division winners (Pittsburgh Steelers and Tampa Bay Buccaneers, respectively) during Wild Card Weekend, the NFL explored another proposal to change the playoffs so that the team with the better record would host the game, even if that meant a division winner went on the road. The NFL's Competition Committee withdrew the request later that offseason, with Atlanta Falcons president Rich McKay mentioning that they wanted the idea to simply get a discussion going. New England Patriots owner Robert Kraft was a strong opponent of the rule change, believing that "if you win a division, it's good for your fans to know you will have a home game." Just before the 2010 Seattle Seahawks won the NFC West at 7-9, and then defeated the 11-5 New Orleans Saints in the opening round, becoming the first team in NFL history to win both a division and later a playoff game with a losing record, McKay stated that he wanted to revisit the previous proposal to reseed teams during Wild Card Weekend. However, sportswriter Peter King wrote that he believes that league owners may still be hesitant on implementing any such changes at this time due to the potential 2011 work stoppage, the proposals to extend the regular season from 16 to 18 games and how it will impact the postseason, and the simple fact that not enough teams have been seriously "jobbed" by the current format. In other words, most of these Wild Card teams with the better records have been able to win on the road anyway; only the aforementioned 2008 Colts and the 2010 Saints were truly disadvantaged by the system.