Cricket DRS LBW Decision Explained
How does DRS adjudicate LBW decisions in cricket? Understand ball-tracking, impact zone, umpire's call, and the full DRS LBW process.
LBW: The Basic Law
Leg Before Wicket (LBW) dismisses a batter when the ball strikes any part of the body (usually the pad) that would have gone on to hit the stumps, provided the batter wasn't playing a legitimate stroke. The ball must not have pitched outside leg stump, and it must not have struck the batter outside the line of off stump if they offered no shot.
What DRS Checks for LBW
When a player reviews an LBW decision, the system checks three things in sequence: (1) whether the ball pitched in line, (2) where it hit the batter (impact), and (3) the predicted path of the ball — would it have gone on to hit the stumps?
Ball-Tracking Technology
Ball-tracking uses high-speed cameras to reconstruct the ball's path from the moment it left the bowler's hand. The system extrapolates the ball's trajectory past the point of impact using physics modelling to predict where it would have gone had it not struck the batter.
Umpire's Call
When the predicted path shows the ball clipping the edge of the stumps — in a marginal zone — the decision becomes 'Umpire's Call.' This means the on-field decision (out or not out) stands regardless of which way the ball is tracking. Umpire's Call exists because ball-tracking has a small margin of error.
Impact Zone
If the ball strikes the pad outside the line of off stump and the batter was playing a shot, the LBW appeal is automatically denied — even if the ball would have hit the stumps. If no shot was offered, the impact outside off stump can still result in LBW.
Review Retention
An unsuccessful review costs a team one review. However, if the on-field decision is 'Umpire's Call' on the outcome — the impact is out but the dismissal ends up with Umpire's Call — the review is typically retained because the decision was so close as to be within the system's error margin.
Frequently asked questions
What is Umpire's Call in DRS?
Umpire's Call means the ball is predicted to be clipping the stumps within the margin of error of the ball-tracking system. When the result falls in this zone, the original on-field umpire's decision is upheld rather than being overturned by technology.
Can you review an LBW if the ball pitches outside leg stump?
No. If ball-tracking confirms the ball pitched outside leg stump, the LBW dismissal is automatically not out — this is one of the fundamental LBW laws and DRS confirms it as the first check.
Why doesn't DRS overturn all close LBW calls?
Because ball-tracking is not 100% precise — it has a small margin of error in predicting the ball's path past the impact point. Umpire's Call protects against overturning decisions that are genuinely within this margin, preserving the umpire's authority for borderline calls.