On the use of unfamiliar bowlers

England just whitewashed Pakistan away from home. Two innings of spin played a major part.

First Test: debutant Will Jacks took six wickets, outperforming xW by 2.5*. Third Test: debutant Rehan Ahmed took five second innings wickets for 48, outperforming xW by 3.5 (ie. on average it was really a 1-point-five for).

Jacks’ performance was on a surface where at one point 882 runs had been scored for the loss of ten wickets. Jacks has only bowled 411 first class overs, and 46 of them were at Rawalpindi.

I have a theory: unfamiliar spinners get a boost, relative to bowlers whose variations have been publicly scrutinised in HD. The boost is measurable by the outperformance vs xW (ie getting more wickets than you’d expect given the quality of balls bowled). We can’t test this directly (I don’t have the data, plus it’s subjective to know who is “unfamiliar”). But we can test a proxy: performances on debut.

The first two columns of the below chart show how it used to be. Lots of promising bowlers get a chance, very few succeed. Most wickets are take by the best bowlers (Murali & Warne) at a low average. These days that trend has reversed.

What’s driving that? I’d suggest it’s the element of mystery – spinners come in many forms, and each has a subtly different style and (possibly) variations. In the 1990s a top bowler may have been able to surprise batsmen with old tricks. Little chance of that these days. Already we know Rehan Ahmed bowls with a high arm, his leg break doesn’t turn as much as the googly, both deliveries have a scrabled seam with lots of topspin. And that’s just from one game.

There are probably some secondary factors, such as better selection, more judicious use of a second spinner, and fewer stars around to bring down the average of non-debutants.

If unfamiliar spinners have an advantage, there is an incentive to give the old ball to any vaguely capable new Test batsman. Keep an eye out for it in future, especially with England.

Take from this that one swallow does not a summer make. Give a spinner a few games to see what he’s made of**. Then we’ll decide if you’ve found the next Swann.

*I think. Didn’t write it down and Cricviz take stats off the app sharpish these days.

** Note the deliberate use of “he” – these stats aren’t based on the women’s game; so it would be inaccurate for me to assume the same principles apply.

Appendices

  1. Leg spinners get better as their careers go on (courtesy of @sanderson_club). Rule of thumb: takes 700 overs to reach their peak.

2. Rehan Ahmed xW – scraped from CricViz’s app.

3. ODI Spin Debutants – Note how wide the gap used to be between debutants and all spinners in ODIs. Just like in Tests.

4. The same trend does not apply for pace bowlers

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