Value of wicket approach
Some time in 2003, I had come across a comprehensive analysis on rediff by name "How valuable is that wicket" (it has been taken offline now I think). It took a weighted batting average of all dismissals by the leading bowlers. They then divided the bowling average of bowlers with their respective weighted batting average of dismissals to come up with a number that roughly represents the % to which a bowler discounts a batsman's average.
I roughly remember these facts: For Marshall, the discount rate was at 69%, Ambrose at 70%, Murali somewhere between 80-90%, Wasim Akram 90%, Warne a few points below Wasim. And towards the bottom were Kapil, Kumble, Willis, Underwood, Bedi etc.
I repeated the same exercise and after spending about 3-4 hours downloading data and sorting it out, I obtained the following:
------------Bowl Ave-------Bat Ave------Discount
Murali--------22.72--------28.51--------79.69%
Warne-------25.41--------29.32--------86.68%
Think that's a very decisive statistic as we spend a lot of time discussing the value of wickets that Murali and Warne have taken. Murali has clearly discounted a batsman's average by about 7% more than that Warne has
It's also telling that those discount factors for Murali and Warne are better than some ATG fast bowlers.
(I am attaching the xls that I worked with)