Quick read: A simple guide to player reviews, umpire reviews, ball tracking and umpire's call.
Player reviews
A batting or fielding side can challenge certain on-field decisions.
Umpire reviews
Officials can check run outs, stumpings, catches and boundaries without a team review.
Ball tracking
Used mainly for lbw to project whether the ball would hit the stumps.
UltraEdge and audio tools
Help detect whether the ball touched bat or glove.
Umpire's call
Protects the original decision when ball-tracking evidence is marginal.
Review retention
Teams usually keep a review when the decision remains umpire's call.
Limits
DRS improves decision-making but still depends on protocols, camera angles and available technology.
DRS is best understood as a review protocol, not a magic answer machine.
Research and reference links
Last reviewed: June 2, 2026. Rankings are editorial where no official all-time ranking exists.