A batter is given out lbw, hesitates, then draws a T in the air. Moments later, television viewers see a reconstructed delivery heading towards the stumps. That familiar sequence is DRS in cricket: a way to challenge certain decisions using evidence that the on-field umpire could not necessarily see or hear in real time.
DRS stands for Decision Review System. It does not replace umpires or promise a perfect answer to every close call. Instead, it gives officials a structured way to examine dismissals using replays, sound analysis and ball tracking.
What does DRS actually review?
The decision review system operates through two routes. In a player review, a team challenges an on-field decision of out or not out. In an umpire review, an official asks the third umpire to check an incident, such as a run-out, stumping or whether a catch was taken cleanly.
A television check for a run-out is not automatically a team using one of its limited player reviews. Equally, DRS cannot be invoked simply because someone disputes a wide, a boundary decision or every other judgment.
How a player review works
Who can request it?
When a batter is given out, the dismissed batter can request a review. When an appeal is turned down, the fielding captain or acting captain makes the request. Players signal a review by forming a T with their forearms. Under ICC protocols, the request normally must be made within 15 seconds after the ball becomes dead, although certain catch referrals have a specific exception.
What happens after the T signal?
The third umpire receives the on-field decision and reviews available evidence in sequence. For an lbw appeal, that usually means checking whether the delivery was legal, whether the ball touched the bat before the pad, where it pitched, where it struck the batter and whether its projected path would hit the wicket.
For a caught-behind appeal, synchronized replays and edge-detection audio may reveal contact between bat and ball. The third umpire communicates a finding, and the on-field official announces the final decision. A ruling changes when the evidence meets the rules for reversal; otherwise, it stays.
The technology behind those television graphics
Ball tracking: predicting the path
Ball tracking in cricket uses camera data to reconstruct the ball’s movement and estimate where it would have travelled after striking a batter. Systems such as Hawk-Eye display three key lbw questions: pitching, impact and wickets.
Pitching identifies where the ball bounced. Impact identifies the point at which it hit the pad or body. Wickets shows whether the predicted path intersects the stumps. These are separate tests: a delivery may head towards middle stump yet still be not out because it pitched outside leg stump.
The projected portion is a model, not footage of something that actually happened. That is one reason the rules recognize marginal cases rather than treating every graphic as absolute certainty. The fundamentals of LBW rules explain the other eligibility tests.
UltraEdge: listening for contact
UltraEdge cricket technology pairs audio from sensitive microphones with video frames showing the ball near the bat. A sound spike occurring at the relevant moment can help establish an edge that was difficult to detect from the field.
But a spike alone is not a verdict. Bat against pad, ground contact and other noises can complicate interpretation. The third umpire looks for timing and visual agreement. UltraEdge and ball tracking answer different questions, so one cannot substitute for the other.
Why umpire’s call keeps the original decision
Umpire’s call is often the most misunderstood part of DRS in cricket. It applies to marginal ball-tracking findings involving lbw impact or whether the ball would have hit the wicket. In those defined situations, the original on-field judgment is retained.
Imagine an lbw appeal is rejected. The fielding team reviews it, and the replay shows a legal ball pitching in line, with impact in line, but only marginally clipping the wicket under the umpire’s-call category. The batter remains not out. If the on-field umpire had given the same delivery out and the other lbw requirements were satisfied, the dismissal could stand instead.
That does not mean DRS produces contradictory measurements. It means the protocol preserves the on-field decision where the specified evidence is marginal. When the decision remains unchanged solely because of umpire’s call, the reviewing team does not lose a review.
How many reviews can a team use?
The allowance is based on unsuccessful player reviews, not every time a team draws a T. Under standard ICC international playing conditions, teams generally have three unsuccessful reviews per innings in Tests and two per innings in ODIs and T20Is. Competition-specific rules should always be checked.
A successful challenge does not reduce the allowance. An lbw decision retained solely on umpire’s call also preserves it. A genuinely unsuccessful challenge uses one. This is why a team’s review count may remain unchanged after a long television check.
When should a team take the risk?
Reviews are tactical resources, particularly near the end of a tight innings. For a caught-behind appeal, a batter who knows the ball hit only the pad has a strong reason to challenge. For an lbw appeal, the fielding captain should consider what the bowler and wicketkeeper saw, including whether the ball pitched outside leg.
A practical viewing tip is to follow the evidence in order rather than jumping to the final ball-tracking animation. Was there an inside edge? Was the delivery legal? Did it pitch outside leg? Those answers can settle an lbw review before the projected wicket path matters. A guide to types of cricket dismissals helps explain why different appeals need different checks.
Frequently asked questions about DRS
Can DRS overturn an umpire’s decision?
Yes. If the evidence satisfies the applicable protocol, an out decision can become not out, or a not-out decision can become out. Marginal lbw evidence may leave the original ruling in place.
Does umpire’s call mean the technology failed?
No. It is a defined category for close lbw impact or wicket predictions. The rules retain the original decision in those cases; they do not declare the equipment broken.
Can players review a run-out?
Run-outs are normally examined through an umpire-initiated television referral, rather than the ordinary player-review process. The third umpire checks evidence such as the wicket being broken and the batter’s ground.
Is DRS used in every cricket match?
No. It is common in major international cricket but depends on the competition’s regulations and access to approved cameras and technology. Smaller competitions may not have the equipment required for full DRS.
Why DRS still depends on human judgment
DRS has changed how players and spectators assess close dismissals, but it works as a partnership between evidence and the laws. Audio helps assess edges, ball tracking helps with lbw, and the third umpire applies the correct threshold for changing a decision. Follow that sequence in the next review, and even a disputed umpire’s call will make more sense.