What Is DRS in Cricket?
DRS stands for Decision Review System. It is a technology-based system used in professional cricket that allows players to challenge on-field umpiring decisions they believe are incorrect.
Before DRS, the on-field umpire’s word was final. If a batsman was given out incorrectly, there was nothing anyone could do. DRS changed that forever. It gave teams a way to seek justice — using cameras, ball-tracking software, and sound-detection technology — when they believed the umpire had made an error.
The International Cricket Council (ICC) introduced DRS at the international level in 2008. Today, it is a standard part of Test cricket and is widely used in ODIs, T20 Internationals, and major domestic leagues like the IPL.
How Does DRS Work? Step-by-Step
Here is exactly what happens when a team decides to use DRS:
Step 1 — The umpire makes a decision. The on-field umpire raises their finger (out) or signals not out.
Step 2 — The fielding or batting team challenges. The captain (or the dismissed batsman) makes a T-shape with their hands to signal a review. This must be done within 15 seconds of the original decision.
Step 3 — The third umpire takes over. The review goes to the third umpire, who sits in a room with access to multiple camera angles and technologies.
Step 4 — Technologies are checked. Depending on the type of dismissal being reviewed, the third umpire checks ball-tracking, UltraEdge, HotSpot, or a combination of these. (More on these technologies below.)
Step 5 — The third umpire gives a verdict. They either:
- Overturn the original decision (the umpire was wrong), or
- Uphold the original decision (the umpire was correct).
Step 6 — Reviews are adjusted. If the review succeeds (decision overturned), the team keeps their review. If the review fails (decision upheld), the team loses one review.
Technologies Used in DRS
DRS is not just one tool — it is a combination of several advanced technologies working together.
Ball-Tracking (Hawk-Eye)
Hawk-Eye uses six high-speed cameras placed around the ground to track the ball’s exact trajectory from the moment it leaves the bowler’s hand. It predicts where the ball would have gone if the batsman had not been there. This is used for LBW decisions — to check whether the ball was hitting the stumps.
UltraEdge (Snickometer / Snicko)
UltraEdge uses a high-sensitivity microphone combined with video to detect the faintest sound the ball makes when it passes the edge of the bat. If the sound spike coincides with the ball passing the bat, it suggests a nick. This is primarily used for caught-behind and LBW reviews.
HotSpot
HotSpot uses two infrared cameras to detect friction heat. When the ball hits the bat or pad, it leaves a bright white mark on the infrared image. It is extremely accurate for edge detection, but it is expensive and not always available on every ground.
Real-Time Snickometer
A faster version of the Snickometer that gives more immediate audio-visual data to the third umpire. It is used when the audio is unclear.
Ball-Spin Axis Tracking
Used for LBW decisions involving spinning deliveries, this technology tracks the exact rotational axis of the ball to confirm its projected path after pitching.
How Many Reviews Does Each Team Get?
The number of reviews depends on the format:
| Format | Reviews per team | Unsuccessful reviews used | Reset |
|---|---|---|---|
| Test Match | 3 per innings | Yes — used up | Every new innings |
| ODI | 2 per innings | Yes — used up | Every Innings |
| T20 International | 1 per innings | Yes — used up | Every Innings |
| IPL | 2 per innings | Yes — used up | Every Innings |
Important: In Test cricket, if a team uses all 3 reviews unsuccessfully, they have no more reviews for the rest of that innings. There is no reset within an innings based on a certain number of overs (unlike some older rules). However, some boards have different rules for domestic leagues, so always check the specific competition’s playing conditions.
When Can a Team Use DRS?
A team can only use DRS for the following types of decisions:
The batting team can review:
- A not-out LBW decision they believe should be out (rare, and teams rarely do this for opponents’ dismissals)
- A caught-behind decision that went against their batsman
- A catch they believe was not clean (the fielder grounded the ball)
- A stumping decision
The fielding team can review:
- An LBW shout that the umpire turned down
- A caught-behind appeal that was turned down
- A run-out decision at the non-striker’s end
- A stumping, the umpire did not give
Teams cannot use DRS for:
- Wide or no-ball calls (with some exceptions in specific playing conditions)
- Boundary decisions in some formats
- Free-hit decisions
What Is the Umpire’s Call Rule?
This is one of the most debated and misunderstood parts of DRS.
When Hawk-Eye tracks the ball’s projected path to the stumps for an LBW decision, there is a margin of uncertainty because predicting the exact path of a cricket ball is not 100% perfect. To account for this, the ICC uses a concept called Umpire’s Call.
Here is how it works:
- If the ball is hitting the stumps fully (more than 50% of the ball hitting more than 50% of the stumps), the decision is changed to OUT regardless of what the on-field umpire said.
- If the ball is clipping the edge of the stumps (only the edge is within the impact zone), it is classified as Umpire’s Call — meaning the on-field decision stands.
Crucially: If a review results in Umpire’s Call, the reviewing team does not lose their review. They keep it. This is a protection mechanism to avoid penalizing teams for decisions that were genuinely too close to call.
DRS in Tests vs ODIs vs T20s
DRS plays a different role depending on the format:
Test Cricket
DRS is most impactful in Tests because the game lasts 5 days, and wrong decisions can completely change the course of a match. Having 3 reviews per innings gives teams significant protection. Captains are generally more strategic about saving reviews for crucial moments.
ODIs
With only 2 reviews per team and 50 overs to play, teams must be tactical. Reviews are often saved for the death overs when a key batsman is at stake.
T20 Internationals
With just 2 review and only 20 overs, the stakes are extremely high for each review. One wrong review can leave a team completely exposed for the rest of the innings — a dangerous position in a format where momentum shifts so quickly.
Famous DRS Moments in Cricket History
Sachin Tendulkar’s “Bowled” vs England, 2011
One of the earliest controversies of DRS. India refused to adopt DRS initially, and many argued that Tendulkar was being protected by the no-DRS policy at the time. The debate fueled massive public discussion about DRS adoption.
Virat Kohli Overturning LBW — India vs Sri Lanka, 2017
Kohli, on a rare not-out review, successfully challenged an LBW decision against him. The ball-tracking showed the delivery was going over the stumps, and Kohli went on to score a century. One DRS challenge, one hundred.
Steve Smith’s Controversial DRS Dismissal — Ashes 2019
A delivery from Jofra Archer struck Smith on the arm guard, and the on-field umpire gave it out. The review showed the ball hit the arm guard outside the line of the stumps. The decision was overturned — Smith survived and batted on.
The Ball That Hit Two Things — ICC World Cup 2019
During the famous World Cup 2019, DRS was used in multiple key matches to decide fine edges and LBW calls that could have completely changed the results. The technology was widely praised for keeping games fair.
Controversies and Criticisms of DRS
DRS is not without its critics. Here are the most common debates:
1. Umpire’s Call is too vague. Many experts argue that the margin for Umpire’s Call is arbitrarily large. A ball clearly hitting the stumps being called “umpire’s call” feels unfair to teams who deserve a clear answer.
2. Hot Spot isn’t always available. Because HotSpot is expensive to set up, it is not used at every ground. This means DRS accuracy varies by venue, which is inconsistent.
3. Teams use DRS strategically, not for justice. Some captains save reviews intentionally to disrupt opponents’ momentum rather than genuinely believing the decision is wrong. This gamesmanship is seen as against the spirit of cricket.
4. BCCI delayed adoption. India’s cricket board (BCCI) was famously reluctant to adopt DRS for years, which meant Test series in India were played without the system. Critics argued this was unfair, especially to touring teams.
5. Technology is not 100% accurate. Hawk-Eye’s predictions are probabilistic, not certain. The system has a stated accuracy margin of error. When a decision rests on a ball clipping a leg stump by millimeters, that margin matters.
Countries That Refused DRS Initially
India was the most notable opponent of DRS for many years. The BCCI (Board of Control for Cricket in India) cited concerns about the accuracy of the technology and had specific issues with ball-tracking predictions. India did not allow DRS in bilateral home series for a long time, making series played in India uniquely non-DRS. Eventually, the BCCI accepted DRS for all ICC events and later for home bilateral series as well.
The debate highlighted a major challenge for ICC — it had no power to force member boards to use DRS, meaning the system’s application was inconsistent for years.
Frequently Asked Questions
Q: Can a batsman review their own dismissal? A: In most formats, the dismissed batsman can signal for a review (making the T-sign), but the final decision to use the review belongs to the team’s captain. In practice, batsmen and captains decide together within the 15-second window.
Q: Can DRS overturn a wide or no-ball? A: In standard playing conditions, DRS cannot be used to review wide or no-ball calls. Some specific T20 leagues have their own rules, so it depends on the competition.
Q: What happens if a team has no reviews left? A: The team simply cannot challenge any umpiring decision for the rest of that innings. The on-field umpire’s word is final once reviews run out.
Q: Is DRS used in all Test matches? A: DRS is mandatory for all ICC-sanctioned Test matches since 2018. Both teams must agree to use it, but for ICC events, it is non-negotiable.
Q: What does “review retained” mean? A: It means the review was successful (the decision was overturned) or resulted in an Umpire’s Call. In both cases, the team gets to keep their review and does not lose it.
Q: Who invented DRS? A: DRS was developed by the ICC in collaboration with several technology companies. The Hawk-Eye system used in DRS was originally invented by Paul Hawkins and was first used in cricket in 2001 for broadcast purposes before being adopted for officiating.
Q: How long does a DRS review take? A: A typical DRS review takes between 60 and 90 seconds. Reviews involving multiple technologies (HotSpot + UltraEdge + Hawk-Eye) can take up to 2–3 minutes in complex cases.
Q: Does DRS apply to women’s cricket? A: Yes. DRS has been used in ICC Women’s events, including Women’s ODI World Cups and Women’s T20 World Cups, since 2014.
Final Thoughts
DRS has fundamentally changed the way cricket is played and watched. It has reduced the impact of human error in officiating, added a strategic layer to captaincy, and made the game fairer at the highest level. While no technology is perfect — and the debates around Umpire’s Call and availability of HotSpot remain — DRS is now an inseparable part of modern international cricket.
The next time when a question pops up in your mind What Is DRS in Cricket, you will know exactly what is happening: a calculated, high-stakes decision where technology, tactics, and cricket’s future are all on the line. Also check out the Super Over rules of cricket as well.
