CRICKET5 min readJanuary 22, 2026
DRS in Cricket Explained: What It Is, How It Works and When Teams Use It
By The Score Central Editorial Team
The Decision Review System gives players the ability to challenge on-field umpiring decisions using a set of broadcast technologies. Each team receives a limited number of reviews per innings, and incorrect reviews are lost. The system is used in international cricket and major domestic competitions including the IPL.
What Teams Can Review
DRS applies only to dismissal decisions. A batter can review a not-out decision (if they believe they are out) or a team can review an out decision (to challenge a dismissal). The most common reviews involve LBW appeals, caught-behind decisions, and bat-pad catches.
Teams cannot use DRS to challenge wide calls, no balls (except for front-foot overstepping, which can be checked by the third umpire independently), or penalty run decisions.
- Reviews available: 2 per innings in Tests, 1 per innings in ODIs and T20Is
- Reviews replenished after 80 overs in Test matches
- Incorrect reviews are lost; successful reviews retain the count
- DRS is not available in all domestic competitions
Hawk-Eye: Ball Tracking for LBW
Hawk-Eye uses 6 or more cameras placed around the ground to reconstruct the path of the ball and project where it would have continued after impact with the batter. For LBW decisions, the key question is whether the ball would have hit the stumps.
If the projection shows the ball hitting the stumps, the on-field decision can be overturned. If the projection shows the ball clipping the edge of the stumps, it enters the Umpire's Call zone, and the original on-field decision stands. This is the most discussed aspect of DRS.
Why does Umpire's Call exist?
Ball-tracking technology has a margin of error of around 5mm due to camera resolution and physics modelling. When a ball is projected to be only marginally hitting the stumps, the error margin means the technology cannot be certain. Umpire's Call preserves the on-field decision in these marginal cases rather than overturning it on uncertain data. Crucially, a decision that remains Umpire's Call does not cost the reviewing team their review.
- Ball must be hitting at least 50% of the stump for an LBW overturning outside Umpire's Call
- Umpire's Call zone: ball just clipping the stumps within the tracking margin of error
- Umpire's Call review is retained by the reviewing team
- Hawk-Eye also tracks whether ball pitched outside leg stump (not LBW)
UltraEdge and HotSpot: Detecting Contact
UltraEdge (also called snicko) detects whether the ball has made contact with the bat by analysing the spike in the audio waveform at the moment of potential contact. A sharp spike at the exact frame of ball-bat proximity indicates an edge. It is generally reliable and is the primary technology used for caught-behind and bat-pad catch reviews.
HotSpot uses infrared imaging to detect heat from friction between ball and bat. It provides visual evidence of contact rather than audio evidence. HotSpot is no longer used in all series due to reliability concerns at lower impact speeds where the heat signature can be too faint to detect.
- UltraEdge: audio spike detection, widely used and reliable
- HotSpot: infrared heat detection, less consistently deployed
- Teams routinely check UltraEdge before committing to an edge review
- Neither technology is mandatory; availability varies by host board
How Teams Use Reviews Strategically
Experienced captains treat reviews as a resource to protect, particularly in Test cricket. Reviews held late in an innings are more valuable because they can challenge LBW decisions against key batters in high-pressure moments. Burning both reviews in the first session on speculative appeals is considered poor review management.
In T20 cricket with only 1 review per innings, the decision to use it is often delayed until a captain or batter has a strong feeling about a specific dismissal decision.
- Save reviews for key batters or critical moments in the innings
- Check available technology feeds before committing to a review
- In T20, the single review per innings makes timing even more important
- Bowling captains often check UltraEdge coverage before deciding on caught-behind reviews
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