Monday, November 14, 2011

McGrath v Warne

As Gideon Haigh once put it 'Warne and McGrath. McGrath and Warne. Who is to decide their proper ordering? Should it be the man with the more wickets or the lower average?' Well, as I've argued here before, the lower average matters but the other relevant statistic for a bowler is not their wickets but their strike rate. A team's chance of winning a cricket match is a function of how quickly they score and how long they stay in, so how could a bowler who takes wickets more quickly and more cheaply than another bowler not be considered more valuable? And on both these measures, McGrath comes out ahead:

McGrath - Average: 21.64; Strike rate: 51.95
Warne - Average: 25.42; Strike rate: 57.49

But hang on, McGrath is a fast bowler and Warne is a spinner. How do they each compare to bowlers of similar characteristics? Well, if you take the average bowling average and strike rate of each of the top 10 spin bowlers and top 10 non-spin bowlers by wickets taken, you get these stats:

Non-spin bowlers - Average: 24.39; Strike rate: 54.88
Spin bowlers - Average: 28.98; Strike rate: 68.89

And if you take each of McGrath's and Warne's bowling averages and strike rates and transform them into a percentage of the corresponding averages just above, you get these figures:

McGrath - Average: -11.2; Strike rate: -5.3
Warne - Average: -12.3; Strike rate: -20.1

So Warne's average is slightly better compared to the top spin bowlers relative to McGrath's average compared to the top non-spin bowlers, but his strike rate is much, much better compared to the top spin bowlers relative to McGrath's strike rate compared to the top non-spin bowlers. Does this mean we're much more likely to see another McGrath than another Warne? It would seem so. Part of the reason why McGrath's figures, and those of non-spin bowlers in general, are better than those of Warne and other spin bowlers could be that non-spin bowlers face easier bowling conditions on average. Think about it: if bowling conditions are good then fast bowlers clean up before the spin bowlers get much of a chance but if bowling conditions are tough then both fast and spin bowlers have to rough it out. I haven't proven this theory yet, so let's just stick with the view that a spin bowler as good as Warne is rarer than a fast bowler as good as McGrath for now. Which, given the trouble Australia has had on settling on a new spinner since Warne's retirement, isn't all that surprising a finding..