We investigate the stat that started all the chat.

What's WASP all about?

WASP is Win And Score Predictor, and it's created a lot of (often heated) discussion on Twitter during the ANZ International Series v West Indies and India, after being included as part of SKY's match coverage. 

WASP was created by Scott Brooker as part of his PHD research, along with his  supervisor Seamus Hogan, at University of Canterbury – and came about almost by accident. 

"We didn't set out to create it - we were working on a high performance management system for NZC, to assess batsmen and their ability to function in certain situations of a match, like 'can they lift their scoring rate' and 'how does that affect their risk or likelihood to lose their wicket'"? 

"As part of this we needed to find a way to accurately calculate a 'game situation' - which is where WASP was born," says Brooker. 

"As you see it on television, WASP predicts the final score in the first innings and estimates the chasing team's probability of winning in the second innings. Because it is based on the average team vs the average team, it's more a guide to who is current winning rather than a prediction of who will win the match. If a strong team is playing a weak team, and the weak team starts well, they will be shown to be winning by the WASP, though they won't necessarily be favourites with the bookmakers."

"Scoring rates and dismissal probabilities are used to make the predictions, which are developed using a complex algorithm based on historical data..

Factors like the history of games at that venue and conditions on the day (pitch, weather etc) are taken into account by the expert opinion - before play starts a 'par score ' is set for that match on that day - recently, this has been set by NZC statistician / guru Francis Payne and the Sky commentary team. 

It's designed to be a guide of what the future holds. A good example was the second Twenty20 match v the West Indies when New Zealand's chase was floundering at about 5% on WASP. "In that situation someone needs to do something special to turn things around, which is exactly what Luke Ronchi did, scoring 51 from 28. WASP got back up to 60-70% in a matter of a couple of overs, which also shows how quickly things change in T20," says Brooker. 

No, WASP doesn't take into account the batsmen at the crease, like when Kohli and Dhoni were on the charge together in Napier - it's a prediction of what would happen at that point of time when the average team is playing the average team. It *does* reflect that batsmen two and three, for example, are going to perform better than batsmen eight and nine  

"You'll also notice greater variances toward the end of an innings - if an opening batsman leaves a ball in the second over, it won't have a great impact on the result as there are plenty of balls left in the innings, but with two overs to go, a dot ball can have a big impact," said Brooker.  

"We wanted to contribute to the sports economics literature - everyone's heard of Money Ball, or even the Sabermetrics movement in baseball, and this is along those lines," said Brooker.   

You can read a more detailed explanation of WASP at Seamus Hogan's blog and find Scott on Twitter at @srbrooker, and follow general cricket stat chat at, erm, #statchat.  

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