A powerful measure of T20I contributions

Ball difference – the difference between the number of runs scored and the number of balls played – is a more appropriate measure of batsmen’s contributions to the final score. We look at T20Is to identify matches in which batsmen achieved a ball difference of varying significance, both positive and negative.

Record-breaking effort: With 156 runs off 63 balls, Aaron Finch gave Australia a ball difference of 93 in its T20I against England in August 2013.   -  Getty Images

When the One-Day format of cricket was launched about 40 years ago, there was no real strategy at play. The format was treated like a shortened Test match. There were no field restrictions, power plays, slower deliveries, optimization of resources, specialist positions and so on. The Indian team would go to the extent of blocking out an entire 60-over innings.

Slowly, the game evolved. In came fielding restrictions, batting strategies to utilise these restrictions, specialist batting and bowling skills, attacking batsmen at the top of the order, pinch hitters, slower deliveries and the realisation that it was fine to hit over the top. The average innings score, which was 225 in the 1970s, now hovers around 280 runs. To put it succinctly, the One-Day International that began life as a shortened Test developed a clear identity of its own.

Indian record: Rohit Sharma’s 118 in 43 balls, which gave him a ball difference of 75, led India to an easy 88-run win over Sri Lanka in December 2017.   -  AP


But the evolution that has taken place in the Twenty20 game – in international matches as well as big-ticket leagues – has been much faster. The format has been in existence for 13 years, and each year has seen tremendous advances. To begin with, the T20 format was seen as a shortened ODI, but it has now become a completely separate game format with many innovations of its own.

The bowler throws down three types of slower deliveries and deliberately aim for the wide tramlines, the off-spinner bowls more leg breaks than the leg spinners and vice versa, the knuckle ball is bowled often, maidens are as rare as an appearance as Haley’s Comet and so on. There is the Dilshan scoop, the reverse flick, the reverse tap and the reverse sweep, and sixes are measures in distance and angles. Fielders practise exotic catches near the boundary and sliding.

If the Test format worked on winning sessions and ODIs required winning groups of overs, the unit of success in the T20 arena is the over. If a team wins two or three overs comprehensively, it is most certain to win the match. And to win an over, each ball has to be treated as an important resource – since a ball comprises more than 16 per cent of the resources the team has – that is, the over. The bowling side puts in as much effort in winning an over as the batting side.

Snail’s pace: M. S, Dhoni scored just nine runs off 27 balls, giving him a ball difference of -18, in India’s loss to Australia in February 2008.   -  AP


And what is a T20 par score? It has moved from the 150-160 of the initial stages of the format to 180-190 nowadays. Let’s peg it at 180 – a very good winning score.

My friend Milind Pandit and I developed a simple-to-use measure called ball difference to analyse a T20 innings. Ball difference, for an innings, is the difference between the number of runs scored and the number of balls played. Let us say that India scores 187. The ball difference for the innings is 67. If the number of extras is nine, the net team ball difference is 58. This is contributed by the batsmen who took strike at various points during the innings. In this article, we are concerned with the ball difference at the batsman and team levels.

Ball difference over strike rate

Let us take two batsmen’s performances within the India innings referred to above. Ajinkya Rahane scores 50 runs in 45 balls and Rohit Sharma scores 10 in 5 balls. The strike rate for each is 111 and 200, respectively. Taken by themselves, the strike rate values present false scenarios. Sharma has seemingly done much better than Rahane. But is this true?

The ball difference is +5 for each of them. This is the bottom line. Rahane and Sharma each contributed 5 to the Indian team’s ball difference of 58. When it comes to evaluating the innings, the fact that Rahane scored more runs than Sharma will allow us to give him credit for that. Sharma’s higher run rate will get him some deserved credit as long as we remember that it was achieved over 5 balls. However, as far as ball difference is concerned, both batsmen have contributed equally.

It is clear that ball difference is a more appropriate measure of batsmen’s contributions to the final score. With this introduction, let me look at T20 internationals to identify matches in which the batsmen have achieved a ball difference of varying significance, both positive and negative.

The higher the better

First, we focus on batsmen with the highest ball difference, in innings where the ball difference was 60 or more.

Innings with the highest ball difference

BatsmanForAgainstRunsBallsStrike rateResultBall difference
Aaron FinchAustraliaEngland15663247.6Won93
Glenn MaxwellAustraliaSri Lanka14565223.1Won80
Rohit SharmaIndiaSri Lanka11843274.4Won75
Richard LeviSouth AfricaNew Zealand11751229.4Won66
David MillerSouth AfricaBangladesh10136280.6Won65
Brendan McCullumNew ZealandBangladesh12358212.1Won65
Faf du PlessisSouth AfricaWest Indies11956212.5Lost63
Evin LewisWest IndiesIndia12562201.6Won63
Babar HayatHong KongOman12260203.3Lost62
Brendan McCullumNew ZealandAustralia11656207.1Won60
Chris GayleWest IndiesSouth Africa11757205.3Lost60


Picture this: Aaron Finch, with 156 runs off 63 balls, has given his team a head start of 93. That means if the other batsmen maintained a run-a-ball rate, the team would have scored 213 runs – enough to win more than 98 per cent of T20 internationals. Similarly for the second and third entries, Australia would have scored 200 riding on Glenn Maxwell’s tour-de-force and India would have reached 195. The team placed last in the table, the West Indies, would have scored 180, which is most often a winning total.

This puts into perspective the true significance of these huge ball difference values. However, it is almost certain that the other batsmen would score at no less than 8 an over. So, these are all going to be huge 200-plus totals. Thus, it seems a high ball difference is almost certainly a recipe for success.

To reinforce the point: the average ball difference for the 32 hundreds scored in T20Is is 54.2 For the 171 scores of 75 and above, the ball difference is 37.1.

As expected, seven out of 10 matches with such innings with a high ball difference have been won by the team concerned.

Dragging the team down

Now we look at the batsmen with the lowest ball difference – innings where the value was -18 or less.

Innings with the lowest ball difference

BatsmanForAgainstRunsBallsStrike rateResultBall difference
Nelson OdhiamboKenyaAfghanistan133636.1Lost-23
Alok KapaliBangladeshSouth Africa143540Lost-21
Shakti GauchanNepalHong Kong52520Lost-20
Niall O'BrienIrelandKenya113032.4Won-19
Sufyan MehmoodOmanUAE133240.6Lost-19
Mahendra Singh DhoniIndiaAustralia92733.33Lost-18
Dwayne SmithWest IndiesIndia112937.9Lost-18
Chamu ChibhabhaZimbabwePakistan82630.8Lost-18
Mohammad HafeezPakistanEngland143243.8Lost-18
Yuvraj SinghIndiaPakistan143243.8Won-18


Facing Afghanistan’s 162, Kenya collapsed to 56 all out. Despite coming in at No.7, Nelson Odhiambo held the innings together, if you can call this painstaking effort an innings, with a Test match-like 13 off 36 balls. As for the second entry, Bangladesh batted first and reached a middling total of 144. Not a bad effort. For reasons of his own, Alok Kapali, coming in at No.6, dawdled to 14 in 35 balls and single-handedly prevented his team from reaching a potentially match-winning 160. In the third row, Nepal had slid to 22 for 7 when Shakti Gauchan walked in. Once the side lost its eighth wicket soon after, Gauchan stoutly defended to reach 5 in 25 balls, and Nepal finished at 72.

Now for a deeper look at the outliers. Two of the 10 matches in the list were won despite the eminently forgettable batting displays of the batsmen concerned. When Ireland met Kenya in 2008, the latter managed to put up only a feeble batting display and reached a total of 67. Ireland then made heavy weather of the chase and took more than 19 overs to reach 72, with Niall O’Brien scoring 11 runs in 30 balls. Well, one cannot complain since Ireland won.

In the second such match, during the Asia Cup in 2016, Pakistan failed miserable and could score only 83. Virat Kolhi batted beautifully and scored 49 in 51 balls, after the side fell to 8 for 3 early on. Meanwhile, Yuvraj Singh ambled to 14 runs off 32 balls. India won, albeit in a laborious manner.

Overall, the average of the 82 batsmen whose ball difference was -10 or below is -12.8.

Batsmen being let down

   PlayerRest of the team Player-team
BatsmanForAgainstRunsBallsBall differenceRunsBallsBall differenceResultball difference
Sompal KamiNepalHong Kong403192689-63Lost72
Babar HayatHong KongOman12260625260-8Lost70
Malcolm WallerZimbabweBangladesh6831375486-32Lost69
Brendan McCullumNew ZealandBangladesh12358656062-2Won67
Richard LeviSouth AfricaNew Zealand117516645450Won66
Jacob OramNew ZealandAustralia6631355080-30Lost65
Aaron FinchAustraliaEngland1566393885731Won62
Kamran AkmalPakistanAustralia6433315687-31Lost62
Tanwir AfzalHong KongScotland5622346390-27Lost61
Hamilton MasakadzaZimbabwePakistan5338153682-46Lost61
Evin LewisWest IndiesIndia125626354495Won58
Glenn MaxwellAustraliaEngland6629375978-19Won56


The third section is the most interesting of all: batsmen who soared while their teammates floundered on the ground. The method is simple: the ball difference of the player minus that of the team, with instances of a net difference of 55 or more being considered.

The first match has already been referred to. Nepal scored 72 as Gauchan finished with a ball difference of -20, a total made possible by Sompal Kami, who came in at the fall of the eighth wicket and scored a brisk 40 in 31 balls – a ball difference of 9 – while the rest made 26 off 89. With the rest of the team having a ball difference off -63, the net ball difference for Kami is an amazing 72, making it seem that he was carrying the entire weight of his team on his shoulder.

Lifting his team: Evin Lewis had a ball difference of 63 as he plundered 125 runs off just 62 balls and the West Indies breezed to a nine-wicket win over India in July 2017.   -  AFP


The discrepancy in performances is as glaring in the next instance, where Babar Hayat scored a magnificent 122 in 60 balls while the rest of the Hong Kong team had a ball difference of -8. After Oman had scored an impressive 180 in the first innings, Hong Kong reached a very competitive 175 for 7. Hayat’s net ball difference for the match was 70 – a value that in most cases would be enough to win the match single-handedly. The rest of the examples follow along the same lines.

Such a comparison can be done between the strike rate of batsmen and their teams, but that wouldn’t give the correct picture. A strike rate ratio of 1.5 could be one between a strike rate of 1.2 runs per ball and 0.8 runs per ball or between 1.8 and 1.2. On the other hand, the difference in ball difference values is a better measure, but it is yet to find wide usage among broadcasters and statisticians.