V. Jayadevan

 D/L system and T20 world cup: Learn how to cut the feet to fit to the footwear.

 

Now it is time for T20 world cup.  It would be interesting to look into the impact of rain interruptions on this event especially when it is played in Sri Lanka, a place where frequent rains are expected.  When no system can slot-in the great uncertainty of cricket, especially in the shootout version of the game like T20, where even a single over can turn around the result, a completely satisfactory MALOT (Method for Adjusting Limited over Targets) is out of question.  But a good MALOT should give freedom to a team to play its normal game without worrying about possibilities of interruption.  The MALOT should not demand a drastic change in game plan like cutting the size of the feet to fit in to the footwear, in view of a possible interruption.   A careful look at the D/L system tells that, it stresses a radical change in game-plan when you foresee the possibility of an interruption.

 

In ODI, when D/L system is criticized for giving superfluous advantage to saving wickets rather than quick scoring of runs, here in T20, one can see just the reverse.  While chasing big targets, even the minimum required importance is not given for losing wickets. It will be very clear if you carefully go through the par score tables 1&2 below. For comparison, the VJD (the closest challenger of D/L system) pars cores are also given.

 

Table-1: Par score for 175 runs in 20 overs

Overs		Par scores corresponding to wickets by D/L and VJD systems
		0	1	2	3	4	5	6	7	8	9
8	D/L	62	64	67	72	78	86	98	116	138	161
	VJD	61	63	63	71	83	97	112	127	142	159
10	D/L	79	80	83	86	90	97	106	120	139	161
	VJD	77	78	78	79	90	103	117	131	144	160
12	D/L	96	97	99	101	104	109	115	125	141	161
	VJD	93	94	95	95	101	112	124	135	147	161
14	D/L	115	115	116	118	119	122	126	133	144	161
	VJD	111	111	111	111	112	121	130	140	150	161

 

In T20, an initial (with in the first 5 overs) loss of 1,2 or even 3 wickets may not significantly affect a team’s overall performance as the remaining wickets are normally sufficient to effectively bat out 20 overs.  But when you lose wickets 4, 5, 6 etc., the situation is not the same as your key batsmen are back.  The par score table above raises a question whether the D/L par scores give adequate allowance for the loss of these wickets.  When it was pointed out that the D/L par scores are quite low in these cases (shown as bold) the ICC reviewer commented that there cannot be a single value of correct par score.  There can be only a range.  In these cases, both VJD par score and D/L par score are within that acceptable range, one is on the lower end and other on the higher end. 

 

When such a dilemma arises, it needs to be further scrutinized with different examples. The best way to clarify it is to look at a slightly border line case.  So let us see how it looks in a 225 runs match (table-2).  This score is also not an uncommon score in T20 matches. 

 

Table-2: Par score for 225 runs in 20 overs

Overs		Par scores corresponding to wickets by D/L and VJD systems
		0	1	2	3	4	5	6	7	8	9
8	D/L	87	88	90	93	98	105	116	133	161	198
	VJD	83	84	85	94	110	128	147	165	183	205
10	D/L	109	110	112	114	117	122	130	143	165	198
	VJD	104	105	105	106	120	136	153	170	186	205
12	D/L	132	132	133	135	137	140	145	155	171	199
	VJD	126	127	127	127	135	148	162	176	189	206
14	D/L	155	155	156	156	158	159	163	168	179	200
	VJD	148	148	149	149	149	160	171	182	193	207

 

Here one can see that the difference is too high (shown as bold) that it is absurd to speak about such an acceptable range having both values included.  So, only one result can be within the acceptable limit (either D/L or VJD). “Which one is that” is what one has to find out.

 

Now look at the table below: Comparison of par-scores corresponding to 5 overs (you can have a result at the completion of 5 overs in T20) in some high scoring T20 matches.

 

Table-3: Blunders in D/L par scores

 

Carefully go through the portions highlighted in table.  Here, par scores corresponding to higher scores are less than the same for lower scores.  For example, if team-2 makes 95/6 at this stage and the match gets interrupted; they win if team-1’s score is 260 or 280, but they lose if it is 220 or 240 and will be a tie if it is 200.   The ICC reviewer who has stated D/L system as more mathematically and statistically robust system (!) is not treating these as serious errors perhaps as it will not occur under normal match situations.  Yes, this may not occur in normal situations, but the impact of such mathematical/statistical anomaly will spread to the normal scoring ranges as well and that is what you have seen in table-1 and 2.  Table-3 is a solid proof for the fact that the D/L par scores in table-1 and 2 are incorrect.  The table-4 below is a confirmation test for that.

 Table-4

Score of team-1 in 20 overs	Stage of Interr-uption  while team-2 is batting	Score of team-2	Overs to which match is re-scheduled	Method	Target	Final situation
200	6	72/4	8	D/L	97	25 in 2 overs
				VJD	107	35 in 2 overs
180	5	64/4	8	D/L	93	29 in 3 overs
				VJD	101	37 in 3 overs
200	5	60/5	10	D/L	129	69 in 5 overs
				VJD	139	79 in 5 overs

In the first row, team-1 makes a big score of 200.  Team-2, realizing the need of the situation, starts from the word goes, and scores fast, but loses 4 wickets in 6 overs during the process.  Now, if the full match is played there is very little chance for team-2 to win.  But if an interruption takes place and only two more overs become possible, team-2 gets almost a 50:50 chance by D/L system, but VJD system does a fair job by maintaining almost the same degree of difficulty for team-2.  Same is the situation in the second row.  In row-3, before interruption there is not even 1% chance for team-2.  But the rescheduled situation opens plenty of hopes for team-2, say at least 25%.

Currently VJD system is the best MALOT available.  But if so many similar examples cited are not sufficient enough to convince the authorities, no one can help.  What the teams can do now is to cut the feet according to the size of the footwear. So, the advice for team-2 is that, if team-1 makes a huge score, and there is a possibility of a rain on cards, do not care about wickets at all. Just go after from the beginning like playing slog overs. Up to 5,6 wickets the increase in D/L par score is very little.  For example, against a score of 225; 132/0 and 145/6 in 12 overs have the same worth (table-2).

ICC may have other priorities than sheer merit in retaining D/L system, but the attitude of BCCI is also very heartrending.  In spite of the technical committee recommending VJD system in 2010 (headed then by Mr. Sunil Gavaskar) they have not yet tried it IPL.  Almost all the Indian umpires and scorers endorse from their 5 years experience in the domestic cricket that VJD system is much better than D/L.  Still BCCI keeps its reservation in promoting VJD system.