How do baseball’s new replay rules compare with the other professional sports leagues that have instituted some form of official review?

Baseball

Begins with series that open Thursday. Applies to home run calls: fair or foul, whether the ball left the playing field, or whether there was fan interference. Decision whether to use replay is made by umpire crew chief. After reviewing video collected at Major League Baseball Advance Media in New York, the crew chief decides whether call should be reversed.

NFL

Began in 1986, not used from 1992-98. Applies to boundary calls involving sideline, goal line, end zone, end line and uprights, plays involving pass completions, incompletions, interceptions, ineligible receivers, forward-pass and fumble calls, whether runners are or aren’t down by defensive contact, forward progress on first downs, touching of kicks, number of players on field, and recovery of loose balls. Under the current system, which began in 1999, a coach gets two challenges per game and can get a third if he is successful on both. If he is unsuccessful, his team loses a time out. In the final two minutes of each half and throughout overtime, there are no coach challenges and a replay official in the press box initiates reviews. The referee, after viewing a monitor on the field, makes the decision. He has 60 seconds to make a decision.

NBA

Began in 2002-03. Used to determine whether a shot was taken before time expired, whether a foul occurred before time expired, and whether 24-second shot clock or eight-second backcourt violations occurred before a shot. Starting with the 2007-08 season, referees were allowed to use replay on severe flagrant fouls and after an altercation to determine whether punches or other unsportsmanlike actions occurred. Referees decide whether to use replays.

NHL

Began in 1991-92. Is used to determine whether the puck completely crossed the goal line, to determine whether it entered the net in compliance with the rules (was not intentionally batted in by a player’s hand, kicked in, or batted in by a stick that was above the height of the crossbar), to determine whether it crossed the line before the net was dislodged, to determine whether it crossed the line completely before time expired in a period and to determine whether the puck deflected directly into the net off an official. Decisions are made at a central location in the NHL’s Toronto office.

Grand Slam tennis tournaments

Began with the 2006 U.S. Open. A Hawk-Eye system is used to decide close line calls, reconstructing the ball’s most likely path by combining its trajectory using images from cameras. Players get three incorrect challenges each set.