Wednesday, November 22, 2017
Updated: Thursday, February 19, 2004
End to All NRR Myths

I am writing this short piece to dispel all myths and confusions about net run rate calculations ahead of the Bangladesh v India U-19 World Cup game tomorrow.

How is the NRR calculated?

First things first. Aggregate all runs scored in all matches of the group stage. This will give us Total Runs (For).

Next aggregate all runs conceded in all group stage matches. This will give us Total Runs (Against).

Now it starts getting a wee bit complicated. Take the sum of the number of overs spent batting. However, there is a caveat. If you lose the match AND are shot out for less than 50 overs, you still count it as 50 overs played. If, on the other hand, your team wins a match AND chased the total in under 50 overs, you count only those overs that were actually played (NOT the full 50). We will call this subtotal "Overs (For)".

Now we need to aggregate the number of overs that all opposing teams spent against us. Again, there is a similar caveat to the case above. If the opponents lose the match AND are shot out in under 50 overs, you still count the 50 overs. If, however, the opponents win the match AND spent fewer than 50 overs chasing the score, you count only the number of overs they actually batted. We will call this subtotal "Overs (Against)".

We now calculate two run rates. Run Rate (For) is given by dividing Total Runs (For) by Overs (For). Similarly Run Rate (Against) is calculated by dividing Total Runs (Against) by Overs (Against).

Finally, the Net Run Rate (NRR) is given by subtracting Run Rate (Against) from Run Rate (For).

Now for a sample calculation using actual scores from the group including Bangladesh in the U19 World Cup. We focus on NRR for New Zealand and Bangladesh only for purposes of illustration.

Runs (For): 202 + 96 = 298
Runs (Against): 204 + 95 = 299
Overs (For): 50* + 12.2 = 62.2
Overs (Against): 49.2 + 50* =99.2

The asterisks (*) indicate that less than 50 overs were actually batted, but since the team was on the losing side, the full 50 have to be counted.

Run Rate (For): 298/62.33 = 4.78
Run Rate (Against): 299/99.33 = 3.01
Net Run Rate = 4.78 - 3.01 = 1.77

Notice also that I converted incomplete overs from their cricketing form to mathematical form. This is a requirement for NRR calculations. In other words, 0.2 overs (i.e. 2 balls) is equal to 2/6 = 0.33.

New Zealand
Total Runs (For): 204 + 146 + 389 = 739
Total Runs (Against): 202 + 215 + 149 = 566
Overs (For): 49.2 + 50* + 50 = 149.2
Overs (Against): 50* + 50 + 50* = 150

Run Rate (For): 739/149.33 = 4.949
Run Rate (Against): 3.773
Net Run Rate: 1.175

Let us now consider some hypothetical scenarios. Consider what would happen if Bangladesh win tomorrow against India, and at the same time, amass a total of around 250. For all intents and purposes, I expect the game to be a close one. Let us assume that we bowl India out for 230. What are the NRR implications?

Bangladesh would have an NRR of 1.336. That would be cause for celebration, as we would pip New Zealand for a spot in the Super League.

But what would happen if the match is a pretty low-scoring affair? Say Bangladesh hit 200 runs batting first, and then bowl India out for 190. Then the Bangladesh NRR falls to 1.163, which is just short of the New Zealand NRR.

As you can see, the NRR can indeed DROP despite a victory.

Bangladesh, therefore, need to do two things. First, win the match. And secondly, post a decent total around the 250 mark. Now, the Indian bowling attack is not that strong. Our batsmen are more or less in form. And the wicket will favour batting. So the chances are not that bleak.

Indeed, if we do play to our potential, then we should progress to the next round along with India.