The Basketball Shot Clock

The rule regarding the basketball shot clock is widely considered to be one that really revived basketball. If you're new to the game, you need to know about it, and what it did for the game.
The shot clock was implemented in the 1950s to speed up the game, and make it more exciting for the viewers. But what is the shot clock, and what are the rules pertaining to it?

Reason for the Shot Clock

In the 1950s, a lot of teams, after gaining possession, would simply hold on to the ball or pass it to their players without making an offensive move. The defensive team resorted to making fouls to regain possession of the ball. This resulted in low-scoring games with lengthy plays, and a large number of fouls. This made the sport boring from the viewer's perspective. Attendance dropped, as people were reluctant to watch slow games. The concept of the shot clock was introduced to increase the pace and tempo of the game, and to make the sport attractive again.

Danny Biasone is largely credited with the implementation of the idea for a shot clock. The rule made it mandatory for the possessing team to attempt a shot every 24 seconds. If the team had possession, but failed to attempt a shot within the stipulated 24 seconds, they conceded a foul, which resulted in a turnover. The rule thus made the play much faster, with emphasis on the attacking moves, hence, making the sport more attractive for the viewers.

Shot Clock Rules

The basic rule is that there will be a timer, set to 24 seconds, counting down to 0. At the end of 24 seconds, if the team with the possession doesn't take a shot, then the possession will be awarded to the opposing team. If the team does attempt a shot, the clock is reset back to 24.

The key element of the rule is player control. It is important that the players of a team gain full control of the ball (as opposed to simply touching the ball) before the clock starts. The clock will start ticking once a player of a team is in control of the ball.

The Attempt
An attempt is a shot taken at the basket, and hits the rim. An attempt needs to be taken, i.e., the ball needs to leave the hands of the player before the alarm goes off, indicating the end of the 24 seconds. If the shot touches the rim of the basket or goes through the basket, the shot is said to be an attempt. If the ball goes in a different direction altogether or misses the basket, then it doesn't count as an attempt, and if the clock has counted down the 24 seconds, it results in a foul.

Inbound Pass
Since it is a clock for a team rather than a player, even after a player of one team has made a pass to a player of his own team, the shot clock does not reset. So, the team can continue passing the ball only for 24 seconds, after which they have to take a shot, or concede the foul. If the player from the opposing team picks up a loose ball after a pass, the shot clock is restarted.

Shot Clock Timings
The timings differ based on the different organizations governing the sport.

NBA24 seconds
WNBA24 seconds
NCAA Men35 seconds
NCAA Women30 seconds
FIBA24 seconds

These were the basic rules governing the basketball shot clock. It has been instrumental in speeding up the game, and thus making it more exciting.