The 30-over factor

Earlier this year West Indies and England played a three-match ODI series that barely registered on the cricket calendar. Yet in the first match, in Antigua, something unusual happened: West Indies, after batting first, slumped to 87 for 4 at the 30-over mark, but finished with a healthy score of 269 for 6, with fifties for Lendl Simmons, Dwayne Bravo and Darren Sammy. In the last 20 overs, they more than tripled their 30-over score. Those runs turned out to be crucial, for West Indies ended up winning by 15 runs.

It was the first time in West Indies' ODI history that their Nos. 5, 6, and 7 all passed 50 in an innings; but what was even rarer was for a team to more than triple their 30-over score in an ODI innings. For a team batting first, this had never happened in 1581 ODIs in the last 15 years.

With wickets in hand, a team usually doubles its 30-over score in one-day internationals.

That's an adage often heard in 50-over cricket, though commentators today also add the rider that scoring patterns have changed recently, perhaps because of the advent of T20s. But was this scoring pattern ever so prevalent, even before the introduction of T20s? When did this sort of scoring occur most frequently, which teams did it, against which opposition, and in what conditions?

All the numbers in this analysis are only from first innings of 50-over matches (excluding curtailed ones), as scoring patterns in chases often depend on the target. Because ball-by-ball data wasn't available earlier, the analysis here is restricted to matches played during the 1999 World Cup, and then again from January 2001. That still leaves us with a database of 1581 matches, though, which is a fairly large number to draw patterns from. We have confined ourselves to the times when teams batting first had the opportunity to bat the full 50 overs. Ball-by-ball data isn't available for three matches during this period, so those games have been excluded.

The overall numbers
In all, this data set covers 1581 matches, out of which there are 526 instances of teams doubling* their 30-over total; that is, in a third - or 33% - of these one-day internationals, teams have finished with scores that are more than twice their 30-over score.

* For the purpose of this exercise, doubling includes all instances of teams getting 100% or more of their 30-over total.

Numbers over the years
Apart from the last year and a half, when the percentage of such results has gone up to 46%, there has been no real trend in terms of such performances over the last 15 years. In some years, like 1999, 2004 and 2007, it went up beyond 37% but didn't stay there for two years in succession. In some other years, like 2009, 2010 and 2011, it hovered between 29% and 32%.

The big difference has been in the period since 2013, when the frequency of such occurrences has gone up by about 35%. Almost half the matches during this period have seen teams double their 30-over score. Perhaps the use of two new balls has allowed batsmen to score more freely in the later overs - assuming harder balls are generally easier to score off. Or are the effects of T20 finally catching up with the 50-over format and influencing it?

Batting teams have perhaps started treating the last 20 overs of ODIs as T20 innings. The average run rate in the first 30 overs of ODIs in the last couple of years is around 4.50, which converts into 135 runs in 30 overs. The average run rate in a T20 innings is around 7.50, which adds up to 150 in 20. Given that teams usually lose a few wickets by the 30th over in ODIs, it's possible to intuitively guess that they have managed to double - or at least target doing so - the 30-over score more often as a result of more T20 batting.

The wickets factor
However, for teams to even start thinking about doubling their 30-over score, they need wickets in hand. The table below lists the frequency of such occurrences as a factor of the number of wickets lost at that stage. When teams have reached the 30-over stage without losing a wicket, they have doubled their total 11 times in 19 innings, or almost 58%; when they have lost seven or more wickets by 30 overs, they have doubled the score from there only five times in 109 innings. Somewhat surprisingly, the percentage for five-down isn't that different from two-down, which suggests that having wickets in hand makes a difference only to an extent.

Wickets aside, the score at the 30-over mark is also important: a team that has scored only 100 at that stage is more likely to double it than one that has scored 200, assuming both have lost the same number of wickets after 30 overs. As the table below shows, when teams have scored less than 120 at the 30-over mark, their doubling percentage is an impressive 45%; however, when they have started well and scored 160 or more after 30, the doubling percentage drops to about 14%.

Out of 20 times when teams have topped 200 at the end of 30 overs, there has been only one instance of a side going on to double that score at the end of their innings. The attack that was torn apart wasn't from an Associate side, but a South African one: in that game in Johannesburg in 2006, when Australia, having already amassed 209 in 30 overs, added another 225 to finish on 434. All of it was in vain, of course, as South Africa won with a ball to spare.

Team-wise numbers
Clearly, there are some line-ups that are more prone to these scoring patterns than others, especially teams with accumulators at the top and hitters lower down. The Pakistani teams of the 1980s and 1990s were good examples of that strategy, especially when playing outside the subcontinent.

The 1992 World Cup final was a prominent example. Pakistan's top four batsmen scored 142 runs from 253 balls, or 42.1 overs, with the main contributors being Imran Khan (72 from 110 balls) and Javed Miandad (58 from 98). After 30 overs, Pakistan were 96 for 2, but they finally finished on 249 after 50, thanks to Inzamam-ul-Haq's 42 off 35, and Wasim Akram's 33 off 18. Together, those two scored 75 off 8.5 overs as Pakistan amassed 153 off the last 20. Those runs turned out to be critical as they won the final by 22 runs. A similar pattern was on view in Pakistan's 1999 World Cup group match against Australia, when a 30-over score of 109 for 3 morphed into a total of 275. The eventual victory margin: ten runs.

Given that the chances of doubling the 30-over score turn remote once a team has lost more than five wickets by that stage, the team-wise analysis only considers instances when teams have lost five wickets or fewer at the end of 30 overs. Out of a total of 1375 such innings, teams have managed to double their 30-over score 498 times, or 36%. Some teams though, have been far more proficient than others. The percentages range from 54 for West Indies to 27.63 for Bangladesh.

Inzamam-ul-Haq's 35-ball 42 helped Pakistan gain a crucial 153 runs off the last 20 overs in the 1992 World Cup final © Getty Images

West Indies have been the most adept at doubling their 30-over score, but that's partly because their score at that point is, on average, relatively lower than those of some other teams. When they are less than six down after 30 overs, they average 126 after 30 overs and 252 after 50, which means, on average, they end up exactly doubling their score; India's average after 30 is 149, which makes it tougher for them to double.

Among West Indies' more memorable such efforts was one against South Africa in the 2003 World Cup, when a 30-over score of 105 for 2 became 278 after 50, thanks to Brian Lara's sparkling 116. West Indies won the match by three runs. Against Pakistan in the VB Series in 2005, they rode on another Lara hundred to get 339, having been 141 for 2 at the end of 30. That performance resulted in a 58-run win. Of 54 such matches, West Indies have won 33 and lost 18 (three were washed out); clearly their batting efforts in the last 20 overs were fruitful more often than not.

New Zealand have generally had a stronger lower-middle order than top order, which is why they are second on the table, with a percentage of almost 45. One of their most impressive performances came in the 2011 World Cup against Pakistan in Pallekele, when Ross Taylor's unbeaten 131 off 124 balls turned a 30-over score of 119 for 4 into a 50-over total of 302. More recently, in 2014 they had two such memorable performances: against India in Napier, a 30-over score of 136 for 2 became a 50-over total of 292, while against West Indies earlier in the season, 133 for 1 converted to 285. New Zealand won both matches.

While West Indies and New Zealand have given some fine exhibitions of converting middling starts into high totals, India have often gone the other way. Against West Indies in Chennai in 2007, they were 206 for 3 after 30 but were bowled out for 268; against the same opposition in St Kitts in 2006, a 30-over score of 179 for 3 became a 50-over total of 245 for 9. There were also instances of 123 for 5 finishing as 170 all out, and 156 for 4 and 144 for 4 ending on 223 and 209 respectively.

India, though, also tend to score plenty in the first 30: they average 149 after 30 when they lose less than six wickets, and 276 at the end of the innings in these matches. That translates to 127 scored in the last 20, which is hardly different from the runs made by New Zealand and West Indies in the last 20 (126 for both). Similarly, for Australia the difference has been the tendency to score more runs in the first 30 - they average 144 during that period when less than six down, and 127 in the last 20.

From a bowling point of view, Bangladesh are the most likely to be at the receiving end of such batting efforts. West Indies and England have percentages of more than 35, while Sri Lanka and Pakistan are at the other end with percentages of around 30. The spread, though, isn't as vast as for the batting teams.

The average 30-over and 50-over scores also vary depending on the opposition. For instance, the percentages against India and South Africa are almost the same, but the average 50-over score against India is 19 more than that against South Africa, which indicates the bowling capabilities of the two teams.

Scoring patterns by host country
Conditions play a part in scoring patterns. In England, where the new ball tends to do more, batsmen have tended to score relatively few runs in the first 30 and then accelerate later. In 41% of matches there, teams have doubled their 30-over score; only in the West Indies and in Zimbabwe has that percentage been higher.

In India and Pakistan, on the other hand, scoring off the new ball is usually a lot easier, which is why the average 30-over score is around 145 in these countries, compared to around 130 in England and the West Indies. However, in Sri Lanka and the UAE, the bigger problem has been to conquer the generally slow conditions and accelerate against the slightly older ball, which is why the scoring rates later in the innings aren't as high as in most other countries.

Overall, when teams have lost five wickets or fewer after 30, they have made an average score of 135 at that point. The average total for teams batting first in these matches is 256, and they have reached the halfway mark, on average, after 28.2 overs. However, if the trend from the last year and a half continues, that mark, and this analysis, will need a relook.

S Rajesh is stats editor and Shiva Jayaraman is stats sub-editor at ESPNcricinfo

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