How does DRS work in cricket?

A captain or batter can challenge an on-field umpire's decision by making a T sign. The TV umpire then checks replays, edge-detection and ball-tracking, and the decision stands or is overturned.

What does umpire's call mean?

The evidence is too close to overturn the on-field decision, so it stands, and the reviewing team does not lose its review.

How many DRS reviews does each team get?

A limited number of unsuccessful reviews per innings. Successful reviews, and umpire's call, do not use one up.

What technology does DRS use?

Slow-motion replays, sound-based edge detection, heat-based imaging in some series, and ball-tracking for LBW.

Cricket · Guide

DRS explained

The Decision Review System lets players challenge an umpire's decision. The TV umpire checks the replays and technology, and the original call either stands or is overturned.

How a review works

After a decision, the batter (if given out) or the fielding captain (if not out) makes a T sign within a few seconds.
The TV umpire checks, in order: was it a no-ball? Did the ball hit the bat? Where did it pitch and hit, and would it have hit the stumps?
The TV umpire tells the on-field umpire, who confirms or changes the decision.

The technology

Replays from many angles, in slow motion.
Edge detection: microphones by the stumps pick up the sound of the ball touching the bat, shown as a spike on screen.
Heat imaging in some series, showing where the ball touched.
Ball-tracking for LBW, projecting where the ball was going. See LBW explained.

Umpire's call

When ball-tracking shows the ball only just clipping the stumps, or the impact is marginal, the TV umpire cannot say the on-field umpire was wrong. It is umpire's call: the original decision stands, and the reviewing team keeps its review.

Running out of reviews

Each side gets a limited number of unsuccessful reviews per innings. Once they are gone, they cannot challenge any more decisions until the next innings, so captains save them for clear mistakes.

Quick answers

How does DRS work in cricket?: A captain or batter can challenge an on-field umpire's decision by making a T sign. The TV umpire then checks replays, edge-detection and ball-tracking, and the decision stands or is overturned.
What does umpire's call mean?: The evidence is too close to overturn the on-field decision, so it stands, and the reviewing team does not lose its review.
How many DRS reviews does each team get?: A limited number of unsuccessful reviews per innings. Successful reviews, and umpire's call, do not use one up.
What technology does DRS use?: Slow-motion replays, sound-based edge detection, heat-based imaging in some series, and ball-tracking for LBW.