DRS explained: reviews and umpire's call
DRS is the Decision Review System. It lets a team challenge an on-field umpire's decision. The third umpire then checks TV replays and technology before confirming or changing the call.
The key points
- The captain or the batter signals a "T" to ask for a review.
- They must signal within 15 seconds of the decision.
- A failed review is lost. A successful review is kept.
- If the result is umpire's call, the team keeps the review.
How many reviews does a team get?
The number depends on the format and the competition. In Test cricket each team normally has two unsuccessful reviews per innings. Limited-overs internationals and leagues such as the IPL set their own numbers, so check the playing conditions of the event.
The technology
- Ball tracking such as Hawk-Eye predicts the path of the ball for LBW decisions.
- Edge detection such as UltraEdge uses a microphone near the stumps to show whether the ball touched the bat.
- Hot Spot, where used, shows heat marks where the ball struck bat or pad.
- Replays check catches, stumpings, run outs and no-balls.
What is umpire's call?
Ball tracking has a small margin of error. So when the prediction is very close, the original decision stands. This happens in two cases for LBW.
- Impact: less than half of the ball hit the batter in line with the stumps.
- Wickets: less than half of the ball would have hit the zone of the stumps and bails.
If the umpire gave it out, it stays out. If the umpire gave it not out, it stays not out. Either way, the reviewing team keeps its review.
Reading the LBW graphic
For an LBW, the screen shows three results in order: pitching, impact and wickets. The batter is out only if pitching is not outside leg, impact is in line, and wickets shows hitting. See the LBW rule for why.
How a review works, step by step
- The on-field umpire makes a decision, out or not out.
- The fielding captain, or the batter given out, makes a T sign within 15 seconds.
- The on-field umpire signals the review to the third umpire.
- The third umpire checks for a no-ball first, then the dismissal itself.
- The third umpire tells the on-field umpire what the replays show.
- The on-field umpire confirms or changes the decision.
Who can ask for a review?
- Fielding side: only the captain can ask. They often consult the bowler and wicketkeeper first.
- Batting side: only the batter given out can ask, sometimes after talking with their partner.
- Signals from the dressing room are not allowed. Umpires can reject a review that seems prompted from outside.
What can be reviewed?
Teams can review any dismissal decision, such as caught, LBW or stumped. Some leagues also let players review wides and no-balls. Many run outs and stumpings are referred to the third umpire by the on-field umpires themselves, without using a team review.
The soft signal is gone
On-field umpires used to give a "soft signal" when referring a close catch. The third umpire needed conclusive evidence to overturn it. The ICC scrapped the soft signal in 2023, so the third umpire now decides these catches from the replays alone.
Why DRS is not used everywhere
DRS needs many cameras, ball tracking and edge detection. That equipment is expensive, so it is mostly used in televised international and major league matches. Domestic and club games are decided by the on-field umpires alone.
A short history
A review system was first trialled in Test cricket in 2008, and DRS was officially launched in 2009. Umpire's call was introduced to account for the small errors in ball tracking. It has been refined several times since then.
Frequently asked questions
What does DRS stand for?
DRS stands for Decision Review System.
Do you lose a review on umpire's call?
No. When the result is umpire's call, the reviewing team keeps its review.
How long do players have to ask for a review?
They must make the T signal within 15 seconds of the on-field decision.
Can the batting team review a not-out decision?
No. The batting side can only review when their batter is given out. The fielding side reviews not-out decisions.
Who checks for front-foot no-balls?
In most international matches, the third umpire checks the front foot on every ball and tells the on-field umpire if it is a no-ball.
Does a team get new reviews in a Super Over?
Competitions set their own rules, but teams usually get one review each in a Super Over.