Yesterday's Article - A Great Question

Further maths focusing on yorkers in T20...

After I wrote about yorkers yesterday I received a great question from Simon on X/Twitter, so I thought I’d post it and then my response - I hope you enjoy it and find it useful. Would be great to hear readers thoughts.

Question:

“Hi Dan, very much enjoyed the IPL yorker thread. If I've got the maths right - not a given - it seems to me that no bowler bowls a yorker often enough to make it a better than average ball.

It seems to me that you need to hit a 43% success rate or better before economy and BPW drop below the average seamer's delivery. Obviously there are loads of variables - Bumrah's full tosses being surprisingly economical for example.

But having fiddled around with various things - including applying a sort of EV to a yorker, where you also take into account the reduction in expected overall runs if a wicket is taken - it doesn't seem a viable delivery at all! The only time its expected econ and BPW is any good is in the death overs, and even that's not great. Does this make sense?

Following on from that, I played around with bowling a deliberate half-volley. Assuming similar "miss" percentages, but that a bowler can hit a half-volley around half the time, it's a slightly better ball for economy than the average ball (9.73 v 9.78) with slightly more chance of taking a wicket (18.33 v 18.79).

Good luck persuading bowlers not to bother with yorkers and bowling deliberate half-volleys...

My Answer:

Hi, yes you are right if you treat the balls completely in isolation.

But here’s where my poker background comes in. Sometimes you have to ‘advertise’ or you might not be able to play your best hands to maximum expectation. Sometimes a regular opponent might have a true/false opinion of how you play [and you can exploit that].

So for example if a bowler only sticks to bowling a good length - because that’s optimal when looking at a ball in isolation - and continues to bowl it, then his good length ball with start to be less effective because batters adapt accordingly and set themselves up for a good length ball because the bowler is too predictable.

So a bowler has to vary their lengths even though some are suboptimal in isolation. The key is to understand when to vary those lengths - which batters are the ones to do it to, and in what conditions, and taking the match situation into account.

As mentioned - would love to hear thoughts.