Umpire’s Call Explained: How the Decision Review System Handles Doubt

The most argued-over phrase in modern cricket is two words long. When a replay graphic flashes orange and the on-field umpire’s original decision stands, viewers often feel the technology has shrugged. In fact umpire’s call is the Decision Review System (DRS) doing exactly what it was designed to do: respecting the margin of error that every measuring system has.

What DRS is, in brief

DRS lets a team challenge an on-field decision and have it checked by the third umpire using technology. According to Wikipedia, the toolkit includes slow-motion video replays, ball-tracking (Hawk-Eye or the similar Virtual Eye), Real Time Snicko, which uses directional microphones to pick up faint sounds of bat and pad, and the infrared imaging system Hot Spot. The page lists Hawk-Eye as using six cameras at 340 frames a second.

The history is not told consistently, even on one page. Wikipedia says player-initiated referrals were tried in an India v Sri Lanka series in 2008 and that the ICC launched the system officially on 24 November 2009, in the first Test between New Zealand and Pakistan at Dunedin. Its account of the first use in Twenty20 internationals contradicts itself (2014 in one place, 2017 in another), so I have left that out. The ODI debut is given as January 2011, during Zimbabwe’s tour of Australia. I could only confirm these dates on that one site, so treat them as provisional.

The logic of umpire’s call

Ball-tracking predicts where a delivery would have gone after hitting the pad. That prediction is a calculation, with a margin of uncertainty. The rule is designed around that margin. Per Wikipedia, in an leg before wicket (lbw) review the original decision is changed only if the technology shows more than half of the ball would have hit the stumps, and the pad was struck with more than half of the ball in line. If less than 50 per cent of the ball is judged to be in line at impact, or less than 50 per cent is judged to be hitting the stumps, the result is umpire’s call. The page adds two distance triggers: an impact 300 cm or more from the stumps, or under 40 cm between where the ball pitched and where it hit the pad, also produces umpire’s call.

In every such case the on-field decision stands. So a batter given out who reviews and sees umpire’s call is still out; a batter given not out stays not out. Two things are worth noticing. First, the rule is symmetrical: it favours neither the bowler nor the batter, only the umpire’s original judgement. Second, it does not apply to every kind of review. The Wikipedia article on the rule says it does not come into play on where the ball pitched, or on whether the batter hit the ball first. Those are matters of fact, settled by replay or sound.

A defence, and the objection

The case for the rule is practical. Without it, a tracking projection accurate to a few millimetres would overturn umpires on a hair’s breadth, and the umpire’s role would become almost decorative. The sport chose instead to say: the umpire is the decision-maker, and technology corrects clear errors.

The objection is equally easy to state. A ball that is 51 per cent hitting is out and one that is 49 per cent hitting is not, even though nobody can truthfully distinguish them. That discomfort is part of the reason the rule has been tinkered with. In my reading, the discomfort is also why the sport has not simply removed the rule: it has no replacement that looks more honest.

How the rule has moved

Cricket.com.au reported on 3 July 2016 that the ICC had amended the protocol after its annual conference. Previously, the tracking had to show that more than half of the ball would hit a zone from the middle of the off stump to the middle of the leg stump, below the bottom of the bails. The new zone extended to the outside of the off and leg stumps, still below the bails, widening it by half a stump on each side. The change took effect from 1 October 2016, or from the start of any DRS series beginning just before that. Wikipedia’s account of the same change is consistent with this, though the two pages differ on which match was first.

A second change concerns what a team loses. Wikipedia says that from late 2017 a team no longer loses a review when an lbw appeal comes back as umpire’s call, and that Test teams stopped getting a top-up of reviews after 80 overs, so each side has two unsuccessful reviews in an innings. The page also states that Test reviews rose to three per innings during the 2020 COVID-19 period and that the change became permanent. The page gives both October and November 2017 for the first change; I have only that one page, so I describe it as ‘late 2017’.

Finally, Wikipedia records that on 4 April 2021 an ICC committee led by Anil Kumble raised the height margin of the wicket zone to the top of the stumps, so that umpire's call margins match for both height and width. That is the form in which the rule is applied now, as far as I could confirm.

How to watch a review

The next time a review happens, it helps to follow it in three steps. First, was the batter hit in line, and where? Second, where did the ball pitch? Third, how much of the ball is shown clipping the stumps? Orange on any of the three means the umpire’s decision stays. Seeing it this way makes the graphic less of a verdict and more of a set of measurements with tolerances, which is closer to what it is. And it explains why teams, and not just tracking engineers, think carefully before spending a review.