DRS (Decision Review System) in Cricket: Complete Guide
How the DRS works in cricket — player reviews, Hawk-Eye, Ultra-Edge, Hot Spot, when teams can review decisions, and the rules around successful and unsuccessful reviews.
The Decision Review System (DRS) is technology-assisted review in international cricket that allows teams to challenge on-field umpire decisions. Introduced gradually from 2008, it is now a standard feature of most international cricket and has significantly reduced high-profile umpiring errors.
How DRS Reviews Work
When an on-field umpire makes a decision a team disagrees with, the fielding or batting captain can initiate a DRS review within 15 seconds. In Tests, each team has 3 reviews per innings (prior to 2019 it was 2); in white-ball cricket, 2 reviews per innings. If the review overturns the decision, the team retains the review. If it upholds the original decision, the team loses the review.
DRS Technology Components
- Hawk-Eye (ball-tracking): Uses multiple cameras to track the ball's trajectory and project where it would have gone. Used for LBW decisions — is the ball hitting the stumps? A 50/50 split exists: the on-field decision stands if the ball is projected to be only partially hitting.
- UltraEdge / Snickometer: Detects audio spikes at the moment the ball passes the bat — indicating an edge. Used for caught-behind and caught decisions.
- Hot Spot: Infra-red cameras that detect heat marks from ball-on-bat contact. Used as additional evidence for edge detection (not always available at all venues).
- Real-time tracking cameras: Multiple cameras at various angles to verify no-balls, front-foot positions, and height of delivery.
The Umpire's Call Rule
One of the DRS's most controversial features is 'Umpire's Call'. When Hawk-Eye's projection shows the ball clipping the edge of the stumps (rather than clearly hitting or missing), the on-field decision stands and the reviewing team retains their review. This preserves the on-field umpire's role but has been criticised for being complex and counterintuitive — particularly when it appears the ball is hitting the stumps.
Captaincy and DRS Strategy
Managing DRS reviews is now a key captaincy skill. A captain who wastes reviews early in an innings — particularly in Tests — can leave their team without recourse when a crucial wicket decision later goes against them. Many teams have a 'review committee' where the captain consults their wicketkeeper and close fielders before deciding whether to review.
Impact on the Game
DRS has reduced the rate of 'howlers' (clearly wrong decisions) significantly. Studies suggest DRS reduces incorrect decisions by 20–30% per series. However, the complexity of Hawk-Eye's projections and the Umpire's Call rule mean DRS reviews can still produce outcomes that appear counterintuitive to viewers.
Frequently asked questions
How many DRS reviews does each team have?
In Test cricket, each team has 3 reviews per innings. In ODI and T20 internationals, each team has 2 reviews per innings. A successful review (that overturns the on-field decision) retains the review. An unsuccessful review loses it.
What is Umpire's Call in DRS?
Umpire's Call applies when Hawk-Eye shows the ball clipping the edge of the stumps — neither clearly hitting nor clearly missing. In Umpire's Call, the on-field decision stands regardless of what was reviewed. The reviewing team retains their review if it was Umpire's Call.
Can umpires initiate DRS?
No — DRS reviews can only be initiated by the fielding team's captain or the batters at the crease. Umpires cannot use DRS on their own initiative. However, TV umpires are brought in to check no-balls and wides without requiring a formal DRS review at some venues.