V Jayadevan points out loophole to be exploited in D/L method if it rains in T20

With the T20 World Cup under way, V. Jayadevan, creator of the VJD system of target revision, recommends throwing bats around whenever rain is in the air, to take advantage of the loopholes in the Duckworth-Lewis system. Arunabha Sengupta looks at the shortcomings of D/L in the Twenty20 format.

With the T20 World Cup under way, V. Jayadevan, creator of the VJD system of target revision, recommends throwing bats around whenever rain is in the air, to take advantage of the loopholes in the Duckworth-Lewis system. Arunabha Sengupta looks at the shortcomings of D/L in the Twenty20 format.

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A match under open heavens

 

Assume this situation: India is playing England at the Premadasa Stadium on September 23. India bat first and Virat Kohli blazes away.MS Dhoni manages to unleash his helicopter strokes with excellent effect, and even Rohit Sharma middles a few. In the end the score reads an excellent 225 in the allotted 20 overs.

 

England, in response, gets off to a flier – reaching 104 for one in just eight overs, and 151 for two from 11 before losing wickets in a flurry. They are 169 for seven at the end of the 14^th.

 

The situation reads as follows – 57 runs are required to win in six overs with three wickets in hand, Stuart Broad and Graeme Swann are at the crease with Jade Dernbach and Steve Finn padded up in the dugout. Ravichandran Ashwin, who has just dismissed the rampaging Eoin Morgan, will bowl two of these overs, Zaheer Khan another two.

 

At this stage, as is forecasted, tropical thundershowers intervene. As it pelts down, players scurry for shelter, groundsmen run in with the covers and the match cannot be continued.

 

When the authorities invoke Duckworth-Lewis (D/L), England emerges victorious. Even though it is almost a lost cause for them, the number of runs is good enough to take them through. They are ahead of the par score for seven wickets – 168.

 

In the 50 over format, the D/L method is conservative, giving far more weightage to wickets in hand, and a low run-rate often suffices in an interrupted game. However, the same system seems to place little value for the wickets in hand in the shortest version.

 

If the match is interrupted after the 10^th over, the par score for a win with just three wickets in hand is 143.Eighty-two runs off the last ten overs is deemed manageable by the algorithm even with just the tail-enders to come.

 

V. Jayadevan, the creator of the alternative VJD method, says that the optimal strategy for teams when there is rain in the air is to go hammer and tongs at the bowling, without a care in the world about keeping wickets intact.

 

Jayadevan’s own system, however, seems far more logical in these circumstances. To win our fictitious match according to VJD, with seven wickets down after 14 overs, England would have to score 182. It certainly is more reasonable to argue that 44 runs off six overs is still gettable with three wickets in hand in a 20 over game. Yet, VJD has been regularly ignored by the International Cricket Council (ICC).

 

A comparison of the two systems in interrupted T20 games

 

The par scores according to the tables given below make us wonder if Frank Duckworth and Tony Lewis have really adapted their scheme for the 20-over format.

 

There is little variation between the systems for situations where 0-4 wickets are lost, with not much deviation for the number of wickets. This is understandable given that in a 20 over game, the remaining number of wickets do not make a lot of difference in the second half of the match if the top order is still at the crease.

 

Par scores chasing 225:

 

Overs	Systems	For wickets lost
		0	1	2	3	4
10	D/L	109	110	112	114	117
	VJD	104	105	105	106	120
12	D/L	132	132	133	135	137
	VJD	126	127	127	127	135
14	D/L	155	155	156	156	158
	VJD	148	148	149	149	149

 

 

 

 

 

 

 

 

 

 

 

 

However, if the number of wickets lost becomes more than five, there definitely is an increased effect of the wickets column in the outcome of the match. It is here that D/L seems way too gradual with regard to the rate at which the target increases for each wicket lost. In contrast, the VJD method definitely looks more tailored to the cause.

 

And finally, the D/L par score suddenly jumps through the sky when nine wickets are lost – making up for lost time and almost catching up with VJD at the very end.

Par scores chasing 225:

 

Overs	Systems	For wickets lost
		5	6	7	8	9
10	D/L	122	130	143	165	198
	VJD	136	153	170	186	205
12	D/L	140	145	155	171	199
	VJD	148	162	176	189	206
14	D/L	159	163	168	179	200
	VJD	160	171	182	193	207

 

 

 

 

 

 

 

 

 

 

 

 

Looking at it with analytical eyes, the root cause for this discrepancy seems that D/L tries to view a T20 match as a 50 over game in which the first 30 overs are cruised through with not a wicket lost.

 

If one looks at the figures in the table marked in bold, there turns out to be more than an indication that VJD provides better and more realistic results in these situations.  However, according to Jayadevan, the standard answer from the ICC reviewer when faced with this discrepancy – among many other such loopholes – has constantly been: there cannot be a single value of correct par score.

 

The situation can be tampered with – the hypothetical first innings score can be varied, as also the number of wickets lost, the overs bowled when the match is interrupted. In most of these cases, the results generated by the D/L method seem to be unrealistic.

 

The questions remain – have the reviews been fair and have all the situations been adequately analysed? The rigidity displayed in moving ahead with the D/L system can have far reaching implications during the T20 World Cup. With so much at stake for the teams, spectators, organisers and sponsors– financially and otherwise – one sure hopes that not everything is washed away by the rains.

 

Till ICC changes its stance, the competing teams will do well to remember the optimal strategy in case of questionable weather conditions – as recommended by Jayadevan himself. Throw caution to the winds and simply concentrate on giving the ball a mighty whack.

 

(Arunabha Senguptais a cricket historian and Chief Cricket Writer at CricketCountry. He writes about the history and the romance of the game, punctuated often by opinions about modern day cricket, while his post-graduate degree in statistics peeps through in occasional analytical pieces. The author of three novels, he can be followed on Twitter at http://twitter.com/senantix)

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