Skip to main content

Keeper Batsman / Batsman Keeper?

Civil War


When I started watching cricket, England was in the grip of a vicious wicket - keeping civil war between the Taylorists (adherents of the smooth, classical technique of Derbyshire's Bob Taylor) and the Knottists (Who championed the rococo brilliance of Kent's Alan Knott).  Like all civil wars it was a terrible thing, splitting families apart, former friends fought each other in the street, there were infamous atrocities and innumerable unrecorded crimes and cruelties.  That conflict has waned in the national consciousness, now it is a part of the heritage industry with reenactments staged by The Sealed Knott Society.  

But in another sense the wicket  - keeping wars have never really left us, through Russell vs Stewart, Reed vs Jones to today's trifecta of Bairstow, Buttler and Foakes to say nothing of Pope.  Are we doomed to always be divided between those who think you pick the best keeper and those who want a bit more ballast in the lower middle order?  This post looks to see if stats can save us from the continual round and round.

Save Us, Stats


The debate is often characterised as balancing the value of a wicket  - keeper as a keeper against the additional runs scored by a superior batsman.  In general journalists and cricket watchers go for the keeper who bats a bit but people who earn a living selecting cricket sides choose the better batsman.  What's always struck me as odd is that the arguments are vigorous but generally fact free. It should, though, be possible to quantify the value of good wicket - keeping as runs and use that to balance out the difference in batting averages between two aspirant keepers.  Part of the reason for this not being the approach is the paucity of cricketing statistics, I think baseball has always systematically recorded fielding errors but cricket scorers have been kinder with drops and duffs.   A very interesting article by Charles Davies on his Z_Scores blog though might provide a route to salvation.  Showing incredible diligence and I hope, for his sake, some nifty IT skills Charles has reviewed the ball by ball commentaries for all test matches from December 2008 - 2016, captured chances of catches and stumpings and whether those chances were taken or missed.  What particularly caught my eye was the postscript where Charles suggested the data could be used as a way of measuring, as runs, the contribution made to the side by a wicket - keeper.

I've taken this idea and tried to see how it might work in practice.  But a word of warning, Mr Davies is a highly intelligent, diligent and statistically skilled man.  I'm none of these things and I suspect what I'm doing with his figures would make Mr Davies wince.  In my defence I'm using an approximation to try and get a feel for the order of magnitude.  So say for instance, I calculate a good keeper can save 30 runs in an innings that's pretty significant and suggests you should always pick a top class keeper, pretty much regardless of batting and the selectors have been doing it wrong.  Then again if a keeper adds two runs an innings with his glove work we would be secure in picking the better batsman in nearly all cases.

The Statistics


Charles Davies' research shows that on average there are seven missed chances in a test match and about a quarter of all chances are missed, giving us a total of 28 chances (taken and missed) in a test match.  There's a very handy table in the article which sets out the 8,000 chances recorded in the period, by fielding position.  Of the total chances, 27% are wicket keeping catches and 3% are stumpings.

Multiplying our total chances a game of 28 by these percentages gives us 7.5 wicket keeping catching chances a game and 0.8 of a stumping chance.  As a test is played by two sides we divide by two to get average catching chances per keeper of 3.8 and average stumping chances of 0.4.

Charles' research tells us an average keeper misses 15% of catching chances and 36% of stumping chances and a wicket is worth 32 runs (not sure where the 32 comes from but I don't think its made up).

So an average keeper misses 3.8 * 15% * 32 = 18 runs of catching value a match, plus
                                               0.4 * 36% * 32=   5 runs of stumping value a match.

So 23 runs of wicket keeping dismissal value.

If we assume a keeper has two innings in each match (Presumably a bit less in reality) then the value of wicket keeping dismissals for an innings is 11.5.  Or to put it another way a perfect keeper who took every chance would be worth 11.5 runs an innings compared to an average test wicket - keeper.


Of course the 11.5 value assumes every catch and stumping is taken but no real world keeper reaches that standard and I'll look at some what ifs in the next section.  First though we need to deal with byes which is another way a good keeper can add value.  Here I've been very broad brush and lent on this blog.  Just by inspection it would seem a top class keeper has a bye rate per 600 balls of a little under three, whilst an average keeper might be around the five mark.  Let's just assume an added value of 2 byes an innings and note here we are comparing average with excellent, not average with perfect.

Some Examples


We are trying to select one of two keepers we'll call them, oh I don't know, Jos and Ben.  We have detailed ball by ball records for both keepers but although Jos has played a fair bit of test cricket Ben hasn't. 

Jos is a bang average test match keeper and so on the basis of my calculation misses 11.5 runs of wicket keeping dismissal value an innings.  Lets assume Ben has a 7.5% miss rate on catches and an 18% miss rate on stumpings, so as a keeper he is half way between an average test keeper like Jos, and God.  Ben's missed chances figure in a match is

Catches = 3.8 * 7.5%*32 = 9
Stumpimgs = 0.4*.18*32 = 2.5


So not surprisingly his value of chances missed a game is 11.5 better than Jos, or 5.75 of added wicket keeper dismissal value an innings. Add in the 2 byes an innings and Ben is contributing 7.75 runs of total wicket keeping value an innings compared to Jos.  Now let's say Jos' test batting average is, roughly, 33.5 (perhaps you should adjust down for not outs to give an innings value?).  If you think Ben can average 30 in test cricket with the bat, he's your wicket keeper.  If you think he'll average 20 Jos is the better option.

But those are only average figures.  Let's assume there is a test to be played on a turning pitch such that each keeper has three stumping chances a match.  Now Jos is giving up 3*.36*32 = 34 runs of stumping dismissals a match with an innings value of 17. Assuming the same lost catching value of 9 per innings gives a total value of missed wicket keeping dismissals of 26 per innings.  Say Ben reduces that to 13 (i.e. he is half way between Jos and God) and add 2 for byes to give 15 of additional wicket keeper value. Now if we think Ben can average 20 odd with the bat he's the better choice.  Actually the choice is even more weighted to Ben as more wicket keeping catches are dropped off spinners than seam bowlers giving the good wicket - keeper an additional advantage over an average keeper.  By the same analysis picking an all seam attack might reduce the value of good keeping to five an innings and there's a better argument for Jos in those circumstances.

The End of The Keeper Wars?


So is that it?  No more endless round and round choosing between wicket - keeper batsmen vs batsman  - keepers?  And to an extent, yes, I think it might be.  Clearly it will require a lot of data on individual keepers but if the ECB aren't doing that as I write someone should be sacked. 

If you look at one past wicket keeper controversy, Alec Stewart vs Jack Russell, I think there is a strong case to be made that Russell didn't play often enough.  Russell had a test batting average of 27.  If you'd played Russell you wouldn't drop Stewart of course but rather the worst batsman in the team.  Let's give that batsman an average of 35 (Mark Ramprakash test average 27 Graham Hick 31).  Now, assuming the gap in wicket  - keeping between Stewart and Russell was the same as between Jos and Ben in our fictional example, then Russell, on an average pitch, gets an added relative wicket keeper value of 7.75 to add to his runs taking him to 34.75.  So his value is pretty much the same as the seventh batsman he is competing with for a place.  But Alec Stewart averaged under 35 with the bat whilst keeping, but over 40 when playing solely as a batsman.  Factor in that additional value and including Russell in the team adds over 40 runs an innings and beats the seventh batsman.

The Chris Read vs Geraint Jones controversy is a bit more of a close run thing.  Read averaged 19 with the bat in tests which, if we assume 7 of added keeper value, gives him a revised average of 26.  Jones averaged 24 with the bat, so the figures are just in favour of Read but of course a lot depends on his real additional value in terms of catches and stumpings, I've just assumed he was halfway between average and perfect and Jones was average

But


I've no real idea how many more catches Jack Russell would take when compared to Alec Stewart or how many more stumpings Chris Read would have got if he had played in Geraint Jones' 34 tests (Jones had 5 stumpings in those matches).  And I wonder if it will turn out keepers we think are clearly superior aren't in terms of statistics.  Cricket is the supreme sport because it appeals to our aesthetic sense as well as our desire for competition.  Do we overstate the case for catches and stumpings made by smooth and natural keepers like Ben Foakes because we enjoy watching them more than a "mechanical" keeper like Jonny Bairstow 

Similarly many cricket watchers, me included, are small c conservatives.  Do we warm to wicket keeping like we warm to thatched roofs, real ale and hand made shoes, examples of old craft skills in an industrialised and commoditised world.  I don't know but it will be fascinating to find out.















                                              

Comments

Popular posts from this blog

County Championship Salary Cap

This is post about salaries in county cricket. The first class counties are subject to a cap and a collar on amounts paid in wages to cricketers.  They must pay above a collar, currently £0.75m, and below a cap, currently £2m. There is an agreement for both the collar and the cap to increase over the next funding round to 2024. In 2024 the collar will be £1.5m and the cap £2.5m What is less clear is what payments count towards the cap and collar.  I assume employers' national insurance (a 13% tax on wages) isn't included.  Similarly I assume payments to coaching staff don't count towards the cap as if they did, Somerset, Lancashire and Yorkshire would all be over the current £2m cap.  I've gone through the accounts of the first class counties to see what, if any, disclosure, they include on players' wages.  What gets disclosed varies enormously, quite a lot for some counties, nothing for others.  Additionally there is a possibility the information include

Mo Bobat and County Cricket

Cricinfo has this  interview with ECB "Performance Director" Mo Bobat.  Bobat makes an interesting claim about county cricket, "Take something like county batting average. We know that a county batting average does not significantly predict an international batting average, so a lot of the conventional things that are looked at as being indicators of success - they don't really stand true in a predictive sense."  And later in the article there is a graph, showing county averages plotted against test averages for 13 English test batsmen.  This is reproduced below. better than random? raw data suggests no meaningful link between championship and test averages 20 25 30 35 40 45 50 55 60 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Test County Championship Sam Curran England players' batting averages

English County Cricket Finance: 2018 Bentley Forbes Rankings

I have gone through the most recent financial statements for the English first class counties,  made an estimate of the financial strength of each and given them a Bentley Forbes Consulting ( TM ) financial sustainability ranking.  The overall table looks like this. County      Profit Assets Ranking Position Essex   4   4   4   1 Surrey   1   7   4   1 Nottinghamshire   5   5   5   3 Somerset   2   8   5   3 Derbyshire   8   3   5   5 Leicestshire    6   6  6   6 Sussex  15   1  8   7 Middlesex  14   2  8   7 Kent     9   9  9   9 Worcestshire    3  15  9 10 Gloucestshire   7  12  9.5 11 Northamptonshire   11  13  12 12 Glamorgan   16  10  13 13 Durham     12  14  13 13 Yorkshire    10  17  13 15 Warwickshire   17  11  14 16 Lancashire   13  16  14 17        The approach is to rank the counties for profitability and balance sheet strength and combine the two measures in a sustainability ranking. The balance sheet strength is itself a combination of thre