Against the Spin

Any cricket fan will tell you that a good-length ball outside the leg-stump will go for more runs than a good length ball just outside the off-stump.  But how many more runs, on average?  That’s where you need some real data to answer the question.  So, in keeping with the theme of this blog, let’s try to quantify scoring & wicket-taking by area of the pitch.

First, let’s look at a bowler’s line and length.  Obviously, this will differ based on whether the batsman and bowler are right or left handed, and whether the bowler is a pace bowler or a spinner.  The handedness of the batsman is accounted for by making the pitch locations relative to the batsman’s off-stump.  The pitch map below shows exactly where pace bowlers land their deliveries.

The totals in the margins indicate that 73% of balls are bowled in the channel outside off stump, and nearly a quarter of balls are bowled short of a good length.  Now let’s look at how fruitful each of these delivery areas is.  Shown on the pitch maps below are the strike rates of batsmen (runs/ball) for balls pitching in that area.

We can quantify the age-old cricketing wisdom that line & length are rewarded.  Good length balls just outside the off-stump go for only about 7 runs per over, while fuller balls are punished at over 9 runs an over.  Similarly, if the bowler strays onto the stumps, the easy on-side runs come at about 9 per over.

The data used to produce the above charts includes all Twenty20 internationals from June to November 2009, plus the 2009 Twenty20 Champions League.  The balls include approximately 4800 balls bowled by fast and medium-fast bowlers.  These pitch maps only include data on right-arm pace bowlers.  Data on left-armers and spinners may appear in a future post.