A shot clock is used in some sports to quicken the pace of the game. It is normally associated with basketball, but is also used in snooker, pro lacrosse, water polo, korfball, and ten-pin bowling. It is analogous with the play clock used in American and Canadian football. In basketball, the shot clock is a timer designed to increase the game's pace (and scoring levels). The offensive team must attempt a field goal (defined as the ball leaving the player's hand and either touching the rim or entering the basket) before the shot clock expires. If the offensive team fails to register a field goal attempt within the time limit, they are assessed a violation resulting in a turnover to their opponents; if the ball hits or enters the rim after the clock expires, it is not a violation so long as it left the player's hand before expiration. The maximum time limit of the shot clock varies by level of play and league: The National Basketball Association has had a 24-second limit since first introducing the clock in the 1950s; men's college basketball has a 35-second limit; and women's basketball has a 30-second limit.
The National Basketball Association had problems attracting fans (and positive media coverage) before the shot clock's inception. This was due to teams running out the clock once they were leading in a game; without the shot clock, teams passed the ball nearly endlessly without penalty. If one team chose to stall, the other team (especially if behind) would often commit fouls to get the ball back following the free throw. Very low-scoring games with many fouls were common, boring fans. The most extreme case occurred on November 22, 1950, when the Fort Wayne Pistons defeated the Minneapolis Lakers by a record-low score of 19-18, including 3-1 in the fourth quarter. The Pistons held the ball for minutes at a time without shooting (they attempted 13 shots for the game) in order to limit the impact of the Lakers' dominant George Mikan. The Pistons' performance led the St. Paul Dispatch to write "[The Pistons] gave pro basketball a great black eye." NBA President Maurice Podoloff said, "In our game, with the number of stars we have, we of necessity run up big scores." A few weeks after the Pistons/Lakers game, the Rochester Royals and Indianapolis Olympians played a six-overtime game with only one shot in each overtime. The NBA tried several rule changes in the early 1950s to speed up the game and reduce fouls before eventually adopting the shot clock.
When it was first introduced by the NBA, the 24-second shot clock made players so nervous that it hardly came into play, as players were taking fewer than 20 seconds to shoot. According to Syracuse star Dolph Schayes, "We thought we had to take quick shots – a pass and a shot was it – maybe 8-10 seconds... But as the game went on, we saw the inherent genius in Danny's 24 seconds – you could work the ball around [the offensive zone] for a good shot." The shot clock, together with some rule changes concerning fouls, revolutionized NBA basketball. In the last pre-clock season(1953–54), teams averaged 79 points per game; in the first year with the clock (1954–55), the average was 93 points, which went up to 107 points by its fourth year in use (1957–58). The advent of the shot clock (and the resulting increase in scoring) coincided with an increase in attendance, which increased 40% within a few years to an average of 4,800 per game.The shot clock received near-universal praise for its role in improving the style of play in the NBA. Coach and referee Charley Eckman said, "Danny Biasone saved the NBA with the 24-second rule." Boston Celtic all-star Bob Cousy, who was notorious for stalling, said, "Before the new rule, the last quarter could be deadly. The team in front would hold the ball indefinitely, and the only way you could get it was by fouling somebody. In the meantime, nobody dared take a shot and the whole game slowed up. With the clock, we have constant action. I think it saved the NBA at that time. It allowed the game to breathe and progress." League president Maurice Podoloff called the adoption of the shot clock "the most important event in the NBA." The league itself states, "Biasone's invention rescue[d] the league."
The shot clock first came to use in 1954 in Syracuse, New York, where Syracuse Nationals owner Danny Biasone experimented using a 24-second version during a scrimmage game. According to Biasone, "I looked at the box scores from the games I enjoyed, games where they didn't screw around and stall. I noticed each team took about 60 shots. That meant 120 shots per game. So I took 48 minutes – 2,880 seconds – and divided that by 120 shots. The result was 24 seconds per shot." Biasone then convinced the NBA to adopt it for the1954–55 season, a season in which the Nationals won the NBA Championship.
Two later pro leagues that rivaled the NBA adopted a modified version of the shot clock. The American Basketball Leagueused a 30-second shot clock for its two years in existence (1961–1963). The American Basketball Association also adopted a 30-second clock when it launched in 1967-68, switching to the NBA's 24-second length for its final season (1975–76). In the 1969-70 season, women's collegiate basketball (at the time sanctioned by the Commission on Intercollegiate Athletics for Women) used a 30-second shot clock on an experimental basis, officially adopting it for the 1970–71 season. Unlike the women's side, there was initial resistance to the implementation of a shot clock for men's NCAA basketball, due to fears that smaller colleges would be unable to compete with powerhouses in a running game. However, after extreme results like an 11-6Tennessee win over Temple in 1973, support for a men's shot clock began to build. The NCAA introduced a 45-second shot clock for the men's game in the 1985–86 season, reducing it to 35 seconds in the 1993–94 season. From its inception in 1975, the Philippine Basketball Association adopted a 25-second shot clock. This was because the shot clocks then installed at the league's main venues, theAraneta Coliseum and Rizal Memorial Coliseum (the latter no longer used by the league), could only be set at 5-second intervals. The league later adopted a 24-second clock starting from the 1995 season. The Metropolitan Basketball Association in the Philippines used the 23-second clock from its maiden season in 1998. In Filipino college basketball, the NCAA Basketball Championship (Philippines) and the UAAP Basketball Championship adopted a 30-second clock; they switched to 24 seconds starting with the 2001-02 season, the first season to start after the FIBA rule change in 2001.
In the NBA (since 1954), Women's National Basketball Association (since 2006), and FIBA play (since 2000; 30-second from 1956 to 2000), the shot clock counts down 24 seconds, thus often being called the "24-second clock." If a shot is attempted and hits or enters the rim, or if the defensive team gains possession via a rebound, steal, or out-of-bounds play, the shot clock resets. Failure by the offense to attempt a shot that hits the rim within the prescribed time results in a "shot clock violation" and a loss of possession to the other team. A buzzer goes off and a yellow LED light strip on top of the backboard illuminates when the shot clock expires. In the 2011–12 NBA season, the last five seconds of the shot clock were modified to include tenths of a second, allowing offensive players to see precisely how much time they have to shoot and officials to determine any last-second shots easily. Furthermore, the shot clock is not reset on a foul in the frontcourt. Rule changes in the NBA since 1998, and in FIBA after 2010 state the shot clock will be reset only if 13 seconds or fewer are on the shot clock, after which it is reset to 14 seconds. The NBA also has a rule on the shot clock reset on jump balls; any jump balls caused by the defense, and the offense keeps control of the ball, should the shot clock have less than 4.9 seconds of time remaining, the clock is reset to 5.0 seconds. Men's college basketball uses a 35-second clock (since 1993; 45-second from 1985 through 1993) in the United States, and a 24-second clock in Canada. Just like in the NBA, the last five seconds of the shot clock is modified to include tenths of a second, which debuted in the 2012–13 NCAA basketball season. Women's college basketball in the United States uses a 30-second clock; in Canada, it uses a 24-second clock. The National Federation of State High School Associations (NFHS), which sets rules for high school basketball in the U.S., does not mandate the use of a shot clock, instead leaving the choice to use a clock and its duration up to each individual state association. Proposals to adopt a national shot clock for high school basketball have been voted down by the NFHS as recently as 2011. Currently, eight U.S. states require the use of a shot clock of either 30 or 35 seconds in high school competition: California, Maryland (girls only), Massachusetts, New York, North Dakota, Rhode Island, South Dakota, and Washington.