Basketball teams have not always alternated possession of the ball. A jump ball, in which a referee tosses the ball into the air between the two teams who attempt to gain control of it, was used by the National Collegiate Athletic Association (NCAA) from 1930 to 1937 both after each basket and when a ball was knocked out of bounds. After 1937, once a basket was made, the ball was given to the other team and jump balls were only used to determine possession for out of play balls. In 1981, the alternating possession rule was enacted. An opening jump ball is used to decide which team gets the ball initially and then alternates during out of play situations.
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