Bowling January 15, 2010

Bowling Power Factor: measuring ODI performances

Based on Alex Tierno's excellent suggestion I had worked on Batting Power Factor; now I have worked on a similar power factor for bowling, with inputs from Anshu Jain.

(This piece has been written in collaboration with Anshu Jain: Updated on Sunday, Jan 16/17)

Based on Alex Tierno's excellent suggestion I had worked on Batting Power Factor - a simple measure to determine the most destructive ODI innings through simple, easy-to-create methodologies. The article was well-received because of the simplicity of the idea. My thanks to Alex.

It follows logically that I should create a similar Power Factor for bowling. I had asked for suggestions. The simplest and most effective suggestion, closest to what I myself was thinking, came from Anshu Jain. My thanks to Anshu.

The requirements are set out below.

1. The methodology should be easy to understand and easy to work out. I have been influenced by Sattvir who mentioned that he wanted to calculate the IPF for each innings as he watches TV. There should be no need to go to the net to get the batsman average or bowler strike rate or whetever. Everything should be available from the Scorecard. A calculator might be needed.

2. The first factor to be recognized is the number of wickets captured. This is the most signicant of a bowler's contributions in a match. It should be recognized that in a 10 over spell, capturing more number of wickets is progressively more difficult. Unlike batting where a batsman can play 150 balls and score 200 runs, here the bowler achieves all in a spell limited to 20% of team overs.

3. The batting position of wickets captured is also important. Not necessarily the batting average.

4. Bowling accuracy is important but only in relation to the team numbers. By itself the bowling accuracy figure means very little as explained below.

India: 150/50 overs (Lee 10-2-25-2,Johnson 10-1-40-2,Watson 10-1-35-1)
India: 250/50 overs (Lee 10-0-45-2,Johnson 10-1-40-2,Watson 10-0-55-1)
Johnson has identical analysis in both matches. However his bowling in the first match is below-par and in the second batch is above-par. Lee has been above-par in both matches and Watson is below-par in both matches.

So the Bowling Accuracy index will be determined based on the bowler's numbers as well as the team's numbers.

I considered briefly and discarded the "% of team wickets" measure since good 4 and 3 wicket performances, where the "% of team wickets" figure was 100, moved up drastically in an unjustifiable manner. This is quite unlike the "% of team score" measure which moves in a 10%-20% band.

Methodology used:

The base is the wicket points. The following are the points allotted. There is a progressive increase for each wicket.

1   2   3   4   5   6   7   8
7  15  25  37  50  64  80  100
To determine the wicket quality, batting position is determined rather than batting average. Anyhow the best batsmen normally bat within no.4. Also if Ponting bats at no.10 his wicket is nowhere as important as at no.4. If a team is reduced to nothing for 3 or 4, it is normally quite difficult to recover. The bowler who captures top order wickets is rewarded and the bowler who captures low order wickets is penalized. This is based on the following formula.
Wickets 1 -  4: 2.0 points
Wickets 5 -  6: 1.5 points
Wickets 7 -  8: 0.75 points
Wickets 9 - 11: 0.25 points
The total for all wickets is added and divided by the number of wickets to arrive at the Wicket Quality Index value. The highest value for WQI is 2.0 (the bowler all whose wickets are 1-4) and the lowest value for WQI is 0.25 (the bowler all whose wickets are 9-11).

The Bowling Accuracy Index is determined by dividing the "Other bowlers' RpO" by the Bowler RpO. The highest ratio value for relevant spells is 10.16 (Walsh's 5 for 1 against SLK). In fact in 3882 such spells only 10 values are above 4 and represent completely bizarre situations, as perfectly illustrated by the Walsh spell. Hence these ratios are first capped at 4.0 and then the square root taken to arrive at the BAI. The index maximum is thus 2.0. This halving is to enure that for a bowler to get a par factor of 1.0, he has to perform at a level twice that of the team. Also to ensure parity with the WQI values. The highest value for BAI is 2.0 and the lowest value for BAI is 0.23.

Now the BPF is determined by multiplying the WP (Wicket Points) by WQI and BAI.

Let us look at the table and the top-20 performances. Only bowlers who captured 3 or more wickets are considered.

No Bowler         MtNo For  Vs  Analysis  WktPts  WQI  BAI   BPF

1 Gilmour G.J 0031 Aus Eng 12.0-6-14-6 64.0 1.71 1.67 182.39 2 Bichel A.J 1976 Aus Eng 10.0-0-20-7 80.0 1.43 1.52 173.32 3 McGrath G.D 1970 Aus Nam 7.0-4-15-7 80.0 1.43 1.41 161.62 4 Johnston D.T 2843 Ire Can 10.0-4-14-5 50.0 1.80 1.79 161.36 5 Mendis B.A.W 2735 Slk Ind 8.0-1-13-6 64.0 1.42 1.77 160.30 6 Muralitharan M 1826 Slk Nzl 10.0-3- 9-5 50.0 1.55 2.00 155.00 7 Imran Khan 0325 Pak Ind 10.0-2-14-6 64.0 1.54 1.56 153.71 8 Bond S.E 1986 Nzl Aus 10.0-2-23-6 64.0 1.58 1.42 143.70 9 Vaas WPUJC 1776 Slk Zim 8.0-3-19-8 100.0 1.41 1.02 143.65 10 Joshi S.B 1504 Ind Saf 10.0-6- 6-5 50.0 1.40 2.00 140.00 11 Edwards F.H 2069 Win Zim 7.0-1-22-6 64.0 1.71 1.28 139.55 12 Simmons P.V 0777 Win Pak 10.0-8- 3-4 37.0 1.88 2.00 138.75 13 Umar Gul 2043 Pak Bng 9.0-2-17-5 50.0 1.65 1.67 137.63 14 Aaqib Javed 0685 Pak Ind 10.0-1-37-7 80.0 1.57 1.07 134.73 15 Vaas WPUJC 1950 Slk Bng 9.1-2-25-6 64.0 1.62 1.28 133.59 16 Wasim Akram 0311 Pak Aus 8.0-1-21-5 50.0 1.90 1.41 133.56 17 Styris S.B 1843 Nzl Win 7.0-0-25-6 64.0 1.50 1.38 132.54 18 Strang B.C 1242 Zim Bng 10.0-2-20-6 64.0 1.62 1.26 131.55 19 Streak H.H 2034 Zim Eng 9.0-3-21-4 37.0 1.88 1.89 131.45 20 Waqar Younis 1724 Pak Eng 10.0-0-36-7 80.0 1.68 0.97 130.43

Gilmour's innspell in the World Cup semi-final, rated by many as the best ever bowling performance of all time, comes in top place. 4 top wickets plus 2 of the next 3, complemented by oustanding bowling accuracy figure, contribute to this top position.

The seven wicket spells of Bichel and McGrath are in the next two positions. Bichel captured wickets 2-8. McGrath's spell included 6 of the top-5. Also note the bowling accuracy of both these spells.

D T Johnston took 5 of the top-6 wickets. Every one knows what Mendis did against India in the Asia Cup Final. He took 3 of the top-6 wickets.

Muralitharan's 5-wkt haul, all in the top-6, coupled with a bowling accuracy which is better than his team's figures by more than 4 times has propelled his performance to the top-5. Imran Khan's 6-14 demolition of India is next, followed by Bond's 6-23 against Australia.

Vaas's best ever ODI bowling effort of 8 for 19 is next. He would have captured all 10 wickets but for the introduction of Muralitharan. Joshi's 5 wickets were in the top-8 and he had an RpO figure of 0.6, way below his team's. This takes him to tenth place.

Note the high placement of Simmons' 4 for 3 against Pakistan. Aaqib Javed's 7 for 30 against India is in 14th position since the bowling accuracy just about matched the rest of the bowlers. Waqar Younis' 7 for 36 finds its way into the top-20.

To view/download the complete 3-wkt bowler list, limited to BPF of 50.0 points and above, please click/right-click here and save the file.

I have created an alternative version of the table based on the suggestion of Unnikrishnan in that I have used the Batting quality total points as it is, without dividing by the number of wickets. This has then been multiplued by the BAI value. The points for the 4 batting groups are 10(1-4), 7(5-6), 3(7-8) and 1(9-11) to get a reasonable final number. To view/download the revised 3-wkt bowler list, limited to BPF of 30.0 points (not comparable to the main table) and above, please click/right-click here and save the file.

I am happy that Gilmour stays on top. A few 7-wkt hauls have been pushed down and great 4-5 wkt spells have moved up because the differential values of the base points has been taken out of the equation.

Anantha Narayanan has written for ESPNcricinfo and CastrolCricket and worked with a number of companies on their cricket performance ratings-related systems