Follow-on: a practice on the wane?

A 3-0 victory margin in a threeTest contest is a potent sign of dominance. And if two out of those three wins are by an innings, one can only acknowledge the level of superiority. India showcased just that in the recently concluded series against South Africa at home.

Out of the three Tests, the second and the third one in Pune and Ranchi respectively ended inside four days. On both occasions, Virat Kohli’s side did not have to bat twice after enforcing the follow on. In doing so, the home broke away from a recent trend in international cricket.

Kohli’s decision took the number of follow-ons in 2019 to three, out of a six possible occasions (when the team batting first had a f i rst i nnings l ead of 200 or greater). Once a common occurrence, captains have often been averse to taking follow-ons over the last decade. Even with a handsome lead, they have often chosen to bat for the second time and set a fourth innings target.

Since 2009, captains have chosen to enforce follow-on less than 50 per cent of the time -- on 46 occasions out of a possible 97.

It wasn’t like this earlier. Even in 2001, when India famously won the Kolkata Test against Australia after being asked to follow on, captains enforced it on all seven occasions when it was available.

The shift happened from 2004 when captains chose to enforce follow-on less than 50 per cent of the time. There is a statistical reasoning behind such change.

From 2000 onwards, in every five-year period, the chances of a win for a team batting first are higher when follow-on is not enforced than when it is.

Despite the evidence of a higher chance of win by batting third, one reason why Virat Kohli might have chosen to enforce follow-on was the magnitude of India’s leads in the two Tests.

If Tests from 2000 onwards are taken, and a logistic regression model is built to predict the likelihood of a follow-on given the magnitude of the first innings lead, the probability crosses 50% at a score of around 270.

With India’s lead in the two matches being 326 (in Pune) and 335 (in Ranchi), a simple logistic regression model predicts that over 70 per cent of captains in this century would have elected to enforce follow-on. Thus Kohli’s decisions on both occasions were understandable, even if they went against modern trends.

100.0%

80.0%

60.0%

40.0%

20.0%

1/2

200