Boundary-hitting is arguably the most important skill in Twenty20 cricket, and is therefore a critical factor in assessing performance. Metrics such as boundary runs and boundary-balls-percentage don’t give us the full picture. A batsman who scores 65% of their runs in boundaries might be below average at rotating the strike. A batsman who hits half his deliveries to the fence could be swinging every other ball.
Ideally, we need to know how often a batsman attempts to hit a boundary and how successful they are when doing so. A boundaries attempted metric will be quite subjective. When a batsman has a big swing, it’s obvious what his intentions are regardless of the outcome. On the other hand, a simple leg-glance for a single might turn into a boundary if timed well enough. It’s also important to consider how the field is set and the situation of the game to give us extra clues about the batsman’s plans. However, without someone sitting down and explicitly recording boundary attempts in every match (as is done with ESPNcricinfo’s control metric) we will have to infer it from ball-by-ball data.
Defining a boundary attempt
Our data records 22 types of shots a batsman could play including all manners of drives, sweeps, pulls and cuts. Using data from over 2,000 T20 matches, we can analyse which types of shots are most likely to result in a boundary.
|shot type||boundary %|
Slog-sweeps result in a boundary 40% of the time followed by upper cuts and scoops on 34%. The top performing shots on the list down to and including reverse sweeps we may reasonably assume are played with the intention to hit a boundary. So let’s draw the line here and use these top 8 shots as our proxy for boundary attempts. Drives and conventional sweeps do result in boundaries but we’re not confident enough that they are always boundary attempts.
We also have data on what connection the batsman makes with each shot.
|batting connection||boundary %|
|Missed (Leg Side)||0|
|Play and Miss||0|
|Play and Miss (Leg Side)||0|
Middling the ball or getting a strong or well-timed connection results in quite high boundary percentages. We will take these three shots to add to our definition of a boundary attempt. Finally we will assume all free hits are boundary attempts.
Boundary attempts in the IPL
In this season’s IPL, there have been 2,484 boundary attempts from the 32 matches so far. That’s nearly 2 per over. Our definition covers 92% of all boundaries scored i.e. about 8% of boundaries are unintentional. The average boundary-success rate across the tournament is 49%.
The graph above shows the boundary success rate broken down by team. This correlates quite well with the current standings; Mumbai Indians have the highest success rate and are one of the form teams at the moment. Contrast this with RCB who have a success rate of 10 percentage points fewer, near the bottom of the table.
Gujarat Lions attempt by far the most boundaries per 120 balls faced. Their batting lineup, which includes Raina, McCullum and Finch, are making a concerted effort to hit as many balls to the fence as possible. However, their below-average success-rate suggests they’re not executing their plans. Interestingly, Mumbai Indians attempt the fewest boundaries of all the teams despite having the highest success rate. The likes of Nitish Rana, Jos Buttler and Pollard are choosing their boundary options with more care and it’s been working effectively so far.
Boundary attempts by player
Let’s take a look at boundary attempts on an individual batsman level. The table below shows the 47 players to have attempted at least 20 boundary hits.
|batsman name||boundary attempts||intentional boundaries||boundary success %||balls faced||balls per boundary attempt|
|AB de Villiers||37||17||46||117||3.16|
Sunil Narine, in his role at the top of the KKR batting order, has the second highest boundary success rate of 68%. He also has the fifth-lowest balls-per-boundary attempt figure – every other ball. At the other end of the scale, Pune’s Ben Stokes has been struggling, producing a 37% success rate. Meanwhile, Stokes’ teammate Ajinkya Rahane attempts a boundary almost every 5 balls – the highest in the list. However he does have the 3rd highest boundary success rate suggesting he is quite picky over which balls to target. This approach is perhaps not serving him so well as he has the lowest strike rate out of the top 20 run-scorers of the season so far.
This boundary-attempts metric has been fairly crudely formulated in this article. But there is clearly potential to lend insight into how teams and batsmen approach a T20 innings, and contribute to a more comprehensive analysis of a side’s performance.
Imran Khan, @cricketsavant