The shot clock is a device that was created in 1954 in an effort to speed up the game of basketball. In the National Basketball Association (NBA), the shot clock is and always has been 24 seconds, while the time varies at other levels of basketball. The shot clock represents the amount of time the team with the ball has to attempt a shot at the basket. If a shot is not attempted before the shot clock expires, it is considered a shot clock violation and the ball is turned over to the defensive team. To avoid a shot clock violation, a shot must be out of an offensive player's hand before the buzzer sounds, and it must at least hit the rim to be considered an attempt.
The introduction of the shot clock changed the NBA forever. Before 1954, extremely low-scoring games were common -- the lowest a 19-18 victory by the Fort Wayne Pistons over the Minneapolis Lakers in 1950. Once a team got the lead in a game, it would often hold the ball and stall while the game clock ran down.
The shot clock prevented that strategy and greatly increased the excitement and fan interest in the game. In 1954-55, the first season of the shot clock, total scoring increased by more than 27 points per game. The Boston Celtics made NBA history by averaging more than 100 points per game. In 1958-59, every team in the league was averaged 100 points per game.
The seemingly arbitrary number of 24 seconds actually came from a mathematical formula created by Syracuse Nationals owner Danny Biasone. Biasone took an average of 60 field-goal attempts per team -- or 120 per game -- and divided it by the 48 minutes in a game. Twenty-four seconds was the average time per shot attempt.
The shot clock was not implemented in men's college basketball until 1986, beginning at 40 seconds and changing to 35 in 1993. Women's college basketball has used a 30-second shot clock since 1970, and the Women's National Basketball Association (WNBA) changed its shot clock from 30 seconds to 24 prior to the 2006 season. The 24-second shot clock is also used in international play.