Decoding the DRS
A study of how the Decision Review System (DRS) is being used by teams in the ongoing World Test Championship
Part 2 of this story, analysing the impact of umpire’s call is available at https://medium.com/kishan19/quantifying-the-impact-of-umpires-call-f00f7d1c80e0
The World Test Championship kicked off with the epic Ashes series in August 2019. I have always been intrigued by the way teams use their referrals in a particular innings. I felt I had some tools in place to start my quest to understand how teams have taken reviews, how crucial have they been, at what stage have teams employed them, and of course, how have the umpires fared. I decided to scrape some data from Cricinfo and Cricbuzz on WTC games (before 10 Dec, so that excludes the ongoing SL-PAK and AUS-NZ series). A bit on the data that was extracted, followed by the insights I am able to see from them.
Data available
Thanks to Cricinfo’s match notes, we have DRS events jotted down for each innings. This can provide a neat compilation of what was the review outcome, who was the batsman at the time of the review, and who was the umpire. I incorporated some derived logic and innings specific data points like the below to add further context.
What was the active partnership at the review incident?
Whether the review incident actually resulted in a break in partnership?
Did the on field decision have to be overturned?
Did the instantiating team lose a review? If so, was it the first occurrence or the second?
With these in hand, I first analyzed how successful teams have been so far with their reviews. Regardless of whether the team was batting or bowling, it is clear from the below, that on average, 50% of reviews are gotten wrong by teams. Since this is in proportion to the number of games teams have played in the WTC, the percentages on the right might give a better understanding of how teams are faring. Intriguing to see the Kiwis 2nd from the bottom in this ratio.
I’ve stripped the batting/bowling context out of the picture above. So, looking at individual numbers from a batsman’s perspectives, I wanted to see the number of times the batsman instantiated the review, and ended up protecting his wicket.
Protection of the wicket is defined through a logical mapping of the review event to the fall of wickets for the said innings. This can be both due to an overturned review, or an umpires call saving the batsman.
I had this theory before I began this study that captains might be the ones who will feel like they would have to take reviews often, because in most cases, they are the most important wickets in the line-up (sorry SPD smith). Joe Root helps me keep the theory alive, showing that he has come out with a 100% survival rate the 5 times he has made the ‘T’.
Mayank Agarwal, Mohammad Mithun of Bangladesh and Wade have been out the most number of times on an umpire’s call [Twice]
Batsman like Nortje and AY Patel appear as they would probably be just using up the remaining review in a last ditch attempt. The active partnership field might be able to explain further, when analyzed at a team level, to understand how aggressive teams go at the opposition top order. By shortening the active partnerships to 3 (and the teams to the big 3) , and differentiating between batting/bowling, we notice the below.
Active partnership refers to the partnership that was active at the time of the referral event
India have instantiated about twice as many reviews on the top 4 of the opposition as compared to the opposition’s reviews against their’s. Of all review events involving India, 75% (24 of 32) have come when they were bowling.
Of course, the success rate is as seen above, but this is yet another evidence why we can see a certain spunk about Kohli’s India.
Let us see how the bowlers have fared. This is a chart of the bowler’s success rates in breaking a partnership, and it hasn’t been a smooth road for the world’s leading test bowler. Cummins has convinced Paine 6 times, but come out successful only once. Early days in the data, so we’ll wait and watch.
Not much of a surprise. Broad, Cummins and Shami were the bowlers at the centre of most referrals sent upstairs. Broad did justice in 50% of the cases. Interesting conundrum for the captains. When my strike bowler asks, do I go up immediately?
The men in the midst
Out. Not Out. Umpires call? Life was much easier as a cricket follower in the 2000s, where a raised finger spelt certain doom. But, not anymore.
What were the number of times the on field call had to be reversed? A quick check so far shows the 1st and 3rd Ashes test 2019 as the two tests with the highest number of overturned incidents.
Just to be sure, here are the ratios.
The 1st Ashes test might be long remembered for Smith’s heroics, but what we cannot let pass is that every 1 in 2 decisions in the Edgbaston had to be overturned. For those wondering who was at the midst of the drama, there is an Easter egg above. But, what next? We can of course further break down these charts to understand the performance of Umpires over the course of a series. We could also observe if the course of umpiring improved/declined over the course of a series, and in between series involving the same umpires as well.
Umpiring is a tough job, we have to admit that. Given the games so far, and referral events, here is how things stand with the umpires. The Ashes has clearly dented Joel Wilson’s numbers, but hopefully it improves over time. Well done to Mr. Gough.
When did teams run out of reviews in their innings?
Well, I kind of reverse engineered this one, taking a cue from the famous 3rd Ashes test of 2019. A brief recap of the timeline of events.
Over 123.6. Pat Cummins to Jack Leach, no run, leg-lined yorker. Leach can’t lay bat, but it’s pitching clearly down leg as he gets pinned on the front leg. There’s barely an appeal, but when desperation hits, why not kill time in reviewing. So the Aussies do, and it’s clearly pitching a foot down (Source: Cricbuzz commentary)
How crucial did this turn out to be, because just an over later, there was this.
I made a chart to see the occurrences of where teams lost their first and second reviews. Of interest is Team India, who have been guilty of emptying their quota twice within the 15th over. Albeit they won both the tests comfortably, this is something to be taken care of as we progress further in the WTC. One of the instances for India was when Bumrah ripped apart WI in the 1st test.
There is lot more that can be analyzed, such as seeing the effect a review had on lengthening a partnership. I will try to delve into those in the coming weeks, but before that I wanted to publish this out to gather feedback on the progress so far. Next on my to do list is to setup an automated data extraction pipeline for all WTC tests from now on. The plan is to make a full fledged dashboard which can update after every game. Hopefully, this will be of value to cricket enthusiasts, players and umpires alike.
Psst…..Cricinfo!
Cheers,
Kishan
