The way batters approach the single tells us there is room for bigger scoring in T20

Scoring rates are higher than a run a ball in T20. In the IPL, a team has scored less than a run a ball without being bowled out 58 times (2.5%) in 2252 team innings (excluding no-result fixtures), and once in the last 552 innings since October 5, 2021.

In T20 a dot ball and a single both mean that the batting side has fallen behind the ask. In ODI cricket, this was only true about the dot ball for most of that format's 54-year history, but scoring rates in ODIs have increased due to changes in the field-setting rules over the last 20 years. Where 300 was once a strong score, it is now merely competitive in comparable conditions. Seven years ago, it was already evident that the single was basically as good as a dot ball in a T20 innings. Today we have not only more data, but a new generation of T20 players - T20 natives if you will - whose records are available for study. What, then, is the future of the single in T20?

Deliveries in T20 can be thought of as being of two types. First, there are deliveries on which either boundaries or wickets occur. Let's call these Type-one deliveries. Second are all other deliveries. Let's call these Type-two deliveries. Bowlers want sequences of Type-two deliveries to be as long as possible; batters want them to be as short as possible, and for them to end in a boundary rather than a wicket. (And Type-two sequences now end in a wicket 20% of the time, down from about 22% in 2008.) The table below shows the average length of the sequence of Type-two deliveries for batters in positions 1-5 in the order in the IPL, and how often such a sequence ends in a boundary for each season.

Though the average length of Type-two sequences has become shorter in the Impact-sub era (2023 onwards), a sequence has not become more likely to end in a wicket, as the last column in the table above shows. A shorter Type-two sequence means that batters are being less selective in the deliveries they choose to attempt to hit for four or six. Though batters are being less selective, they are not less successful at scoring the boundary than they were before the Impact substitute was introduced. The combination of the shortened Type-two sequence and the slightly increased frequency with which the sequence ends in a boundary suggests improved efficiency in spending wickets, and improved skill.

The Impact substitute does allow teams to play the extra batter, increasing the depth of the batting line-up. But it also enables teams to play the extra bowler, increasing the depth of the bowling attack, and allows teams to reserve one of their specialist bowlers for the last ten overs of the innings - as Chennai Super Kings often do with Matheesha Pathirana, and Mumbai Indians sometimes do with Jasprit Bumrah. In terms of outcomes, it seems to favour batters, as the shortening of the average length of Type-two sequences since 2022 shows.

The average score at the end of ten overs in an IPL innings between 2013 and 2022 was 75.6 runs for 2.3 wickets. In the Impact-sub era, it is 87.6 runs for 2.5 wickets. The number of Type-two deliveries in the first ten overs of the innings has declined. One in four deliveries in the first ten overs of the innings in the IPL are now Type-one deliveries. In the early seasons of the IPL, one in five were Type-one deliveries.

While these numbers suggest that teams are being less negative with the bat in the first half of T20 innings, this batting advance is still in its infancy. For example, while openers in the IPL are scoring quicker earlier, they are not yet trading survival for runs (see the graph below). The striking thing about the Impact-sub era has been that quicker scoring by IPL top orders has not brought with it a significant shortening of the IPL opener's innings. This suggests that the average opener in the Impact-sub era is just basically better at strokeplay than his counterpart from the pre-Impact-sub era.

The inefficiency that has been exploited so far has been the relatively limited ability of openers in the early seasons of the IPL to access undefended boundaries on the field. New strokes have been cultivated that allow boundaries to be scored all round the wicket. The 360-degree top-order IPL batter is now commonplace, where once they were a rarity (in fact, the term was associated with one player, AB de Villiers, before Suryakumar Yadav came along).

ODI cricket provides a good case study for the type of top-order efficiency there will likely be in the IPL in the future. In 50-over matches before 1990, the average ODI opener's innings was 30 in 51 balls. In the 1990s, this changed to 31 (46 balls), in the 2000s to 32 (41), in the 2010s to 35 (41), and in the 2020s to 38 (40). (ODIs of 60 and 45 overs, and rain-shortened matches have been excluded in this analysis. Also, only matches involving the eight oldest Test-playing nations are included, for the sake of continuity.)

In the IPL, by contrast, the average opener's innings has gone from 26 (21) in 2008-12 to 31 (21) in the Impact-sub era. A more significant shift has occurred in batting positions three and four, where the average innings has gone from 23.6 (19.3) in the first period to 26.3 (17.7) now.

On the whole, even in the Impact-sub era, T20 batting is significantly more cautious than ODI batting. ODI teams were bowled out in 29% of innings in the 1980s, and averaged 216 runs per 300 balls. In the 2020s, they have been bowled out in 38% of innings, and average 289 runs per 300 balls (50-over matches between the eight oldest Test-playing teams). In the IPL, in contrast, teams were bowled out in 9% of innings in the 2008-12 period for an average score of 158. In the Impact-sub era, this has changed only marginally, to 10%, while the average score has increased to 186.

All this suggests that the recent increase in scoring in the IPL has been due to a general improvement in two abilities of the average batter playing in the top eight batting positions in the IPL. First, the ability to target the undefended boundary. Second, the ability to hit sixes. The increase in scoring does not yet suggest a significant shift in the approach of batting sides when it comes to spending wickets.

One example of this increasing ability is the scoring rate against fast bowlers when they pitch on the "hard" length of 7-8 metres from the stumps. In the first 15 years of the IPL, when a fast bowler hit that length, the bowling side could be confident of conceding roughly one run per ball (102 runs per 100 balls faced). A six was hit once every 35 balls against fast bowlers on that length. In the Impact-sub era, eight runs per over are scored from this length (135 runs per 100 balls faced), and a six is hit once every 17 balls on his length.

The fact that the Impact substitute has produced an increase in scoring rate, even though it has enabled most teams to play both an extra batter and an extra bowler (and not rely on a part-timer for overs) suggests that hitters have significantly greater leverage when compared to bowlers. This is not surprising since the scarce resource for the batting side in the T20 is the number of balls and not the number of wickets (unlike in longer forms of the game, where wickets are the scarce resource). But the type of improvement in efficiency seen in the ODI game from the 1980s to the 2000s has not been evident yet in the IPL.

The next stage for the IPL is most likely to be when teams harness this improved ability to spend their wickets more efficiently. To illustrate this, consider the following example.

Suppose Chennai Super Kings have lost four wickets, and it is the 14th over of their innings. Shivam Dube is batting with Sam Curran and the bowling side puts an offspinner on to bowl with Dube on strike. Should Dube take a single first ball and get off strike? Curran has scored at 105 runs per 100 balls against offspin in the IPL in the Impact-substitute era, while Dube's scoring rate against offspin in the same period is 131.

Currently, the conventional wisdom in the IPL is that yes, Dube should take the single, so he does not have to face the ball spinning away from him. There have been instances of players refusing singles, but these are mostly in the last two or three overs, when a tailender is at one end (say, Hardik Pandya batting with Trent Boult). But refusing singles with only four wickets down in the 14th over to maintain a favourable match-up is currently non-existent in the IPL. Having Dube chase boundaries single-mindedly against the offspinner in the 14th over increases the risk of him being dismissed, but it also increases the number of runs that are likely to be scored in that over. In the next stage of the IPL's advancement, it will be the conventional wisdom for Dube to refuse the single and stay on strike for most if not all of the offspinner's over - to trade the increased risk of dismissal against more runs from the over.

The table below shows the outcome of an over by the number of times the strike changes during the over in the IPL. In the Impact-sub era (2023-25), an over in which one player plays out the whole over produces 12.7 runs per over on average. With one change of strike, this falls to 10.5 runs per over, with two changes of strike, 9.5.

Despite this increase in scoring rates, the frequency of overs that have 0, 1 or 2 strike changes remains unchanged (58%) in the Impact-sub era (note that a change of strike can occur either because an odd number of runs are scored, or because a wicket falls).

The single has signified different things in the history of the game. In Test cricket it meant a batter getting off strike, which, especially against a particularly testing spell, was desirable from the point of view of the batter's survival. In ODI cricket, it meant "keeping the scoreboard moving", and the relatively risk-free accumulation of runs against a deep-set field. So far, this meaning has generally been adopted in T20.

In the future, in T20, the single will mean one of two things. First, that the batting side thinks that both batters at the crease are equally capable of scoring boundaries against the bowler of that over. Second, that the batting side thinks the non-striker is more capable of scoring boundaries against the bowler of that over than the striker, and so the strike needs to change. T20 is not quite there yet. But that is the future of the single in T20.