Is there selection bias towards Australian players in the IPL?

23rd May, 2018.


There has been much discussion in the media in recent days about perceived bias towards Australian players in the IPL, with Graeme Smith (on Select Dugout) and Graeme Swann (on Cricinfo) both of the opinion that Australian coaches are selecting their countrymen, to the detriment of players of other nationalities.  

Are coaches picking more players of their own nationality?

It's easy to be caught up in speculation and a look at the numbers suggests that this isn't nearly as prevalent as in previous years:-

Year

Players Selected by Coach of same Nation

Teams

Players/Teams





2008

15

8

1.88

2009

22

8

2.75

2010

21

8

2.63

2011

28

10

2.80

2012

16

9

1.78

2013

13

8

1.63

2014

11

8

1.38

2015

11

8

1.38

2016

11

8

1.38

2017

11

8

1.38

2018

12

8

1.50


We can see from the data that this phenomenon peaked between 2009-2011, with almost 3 players per team being of the same nationality as their coach, but has dropped off noticeably in recent years.  

Which countries do IPL coaches come from?

Country

Coaches

%

Coaching Years

%






Australia

13

43.33

43

46.24

India

4

13.33

9

9.68

New Zealand

4

13.33

18

19.35

South Africa

8

26.67

21

22.58

Sri Lanka

1

3.33

2

2.15


The table above illustrates the country split of IPL coaches since the inception of the IPL in 2008, and it markedly obvious that Australian coaches dominate the coaching set up, with 43% of all coaches in the IPL from 2008 onwards being Australian, and 46% of the coaching years been performed by Australian coaches.

Over 80% of coaches and coaching years have come from Australia, New Zealand and South Africa combined, and worth debating is whether these countries produce better coaches, or simply that they benefit from a schedule in their home nation which doesn't clash with the IPL.  Certainly this is to the detriment of English coaches, when the county season clashes with the IPL, which is a shame - it would be great for an English T20 coach with a great record, such as David Ripley, get an opportunity in the IPL.

Do Australian players pick more of their countrymen than coaches of other nations?

The simple answer to this question is yes - Smith and Swann were spot on.  The table below illustrates the coaches with the highest number of same nation players per year coached:-

Coach

Nation

Years

Same Nation Players

Players/Year






Adam Gilchrist

Australia

1

4

4.00

Darren Lehmann

Australia

5

20

4.00

Geoff Marsh

Australia

1

4

4.00

Michael Bevan

Australia

1

4

4.00

Greg Shipperd

Australia

4

15

3.75

Gary Kirsten

South Africa

2

7

3.50

Shane Warne

Australia

5

16

3.20

John Buchanan

Australia

2

6

3.00

Ray Jennings

South Africa

5

14

2.80

Brad Hodge

Australia

3

8

2.67


Of these coaches, eight of these coaches were Australian, and when the data is condensed as below, the bias from Australian coaches to Australian players is obvious:-

Country

Players/Year



Australia

2.78

New Zealand

0.78

South Africa

1.95

Sri Lanka

1.00


Australian coaches picked almost one countryman more per year than the next highest nation - South Africa - while New Zealand coaches have rarely trusted New Zealand players.  Stephen Fleming has barely ever picked a player of his home nation, while Daniel Vettori didn't until this year, when his bizarre experiment of loading the RCB squad with New Zealanders backfired.

Why do Australian coaches pick Australian players?

It's easy for lazy observers to suggest that they just pick their mates, or make accusations that it is simply a 'back-scratching exercise', so it's worth going a little deeper into trying to explain this phenomenon.  Certainly, there's probably a little influence coming from knowing the player, and when done in the right manner and judging each player on their merits, this can easily be a positive as opposed to a negative.  

However, it's worth looking at the performance of Australian players in the IPL throughout the years - if they are considerably better than the average player, then such a stance from Australian coaches can be justified.  Having said this, we must measure Australian players against fellow overseas players, as opposed to simply the average player.  Given selection constraints on overseas players and the scarcity of that particular resource (maximum four out of 11 in a team) compared to domestic players, we cannot compare them to domestic players.

The table below illustrates the performances of Australian players versus overseas players from 2008 onwards (2018 data correct at the end of the league phase).  A positive mean deviation means that Australian players performed better than the average overseas player, while the overall batting mean deviation in the last column is a 50-50 split between average and strike rate mean deviation.

Year

Overseas Batting Ave

Overseas Batting SR

Australian Batting Ave

Australian Batting SR

Australian v Overseas Batting Ave Mean Deviation

Australian v Overseas Batting SR Mean Deviation

Australian Overall Batting Mean Deviation









2008

26.91

134.02

35.42

136.39

1.32

1.02

1.17

2009

26.55

120.86

27.28

128.97

1.03

1.07

1.05

2010

25.29

127.24

23.65

126.55

0.94

0.99

0.96

2011

25.23

122.50

24.95

119.06

0.99

0.97

0.98

2012

27.73

126.30

30.45

129.25

1.10

1.02

1.06

2013

25.82

126.40

29.08

125.47

1.13

0.99

1.06

2014

28.65

133.28

28.96

137.09

1.01

1.03

1.02

2015

29.34

138.20

24.80

134.38

0.85

0.97

0.91

2016

26.69

137.73

29.88

134.52

1.12

0.98

1.05

2017

25.86

138.73

31.19

141.96

1.21

1.02

1.11

2018

25.44

141.08

22.23

133.91

0.87

0.95

0.91


We can see that in the first two years of the IPL, Australian batsmen thrived, particularly in 2008, where the likes of Shaun Marsh and Shane Watson flayed bowling attacks to all corners.  However, this calmed down from 2010 onwards, and there were a similar amount of good seasons to bad seasons for Australian batsmen subsequently.

The worst performance from Australian batsmen has come in 2015 and this year, 2018.  However, the dynamics are rather different - in 2015 they performed better (higher average and strike rate) than 2018, but this year generally has heralded one of the worst years for overseas batsmen from an average perspective, so they are measured against a lower standard this year.

Overall, it's probably fair to suggest that Australian batsmen have historically been of a marginally higher standard than their overseas rivals, but there really isn't much in it.  It's also probably reasonable to conclude that the media have been victims of recency bias (more on this later) by over-reacting to poor performances by Australian players this year - if this continued over the next season or two, then there would be more weight to this.

However, there were less positives for Australian bowlers, as can be seen below:-

Year

Overseas Bowling Ave

Overseas Bowling Econ

Australian Bowling Ave

Australian Bowling Econ

Australian v Overseas Bowling Ave Mean Deviation

Australian v Overseas Bowling Econ Mean Deviation

Australian Overall Bowling Mean Deviation









2008

27.18

7.76

29.67

8.04

0.92

0.97

0.94

2009

27.51

7.24

27.35

7.31

1.01

0.99

1.00

2010

28.98

7.81

29.92

7.66

0.97

1.02

0.99

2011

26.70

7.49

26.97

7.49

0.99

1.00

1.00

2012

24.12

7.37

24.59

7.48

0.98

0.99

0.98

2013

25.21

7.61

26.03

7.86

0.97

0.97

0.97

2014

31.43

8.10

29.03

8.57

1.08

0.94

1.01

2015

25.57

8.20

27.78

8.32

0.92

0.99

0.95

2016

28.60

8.25

26.14

8.23

1.09

1.00

1.05

2017

29.19

8.37

28.00

8.42

1.04

0.99

1.02

2018

29.27

8.62

29.85

8.94

0.98

0.96

0.97



Here, in only three years (2014, 2016, 2017) did Australian bowlers out-perform their overseas rivals, and generally, Australian bowlers have been slightly below the standard of the average overseas bowler in the IPL.  This phenomenon is very logical, with conditions markedly different between the two countries, and is something that I have noticed previously, with my IPL algorithm making the transition from the BBL to the IPL generally a rather difficult one.

Overall, Australian batsmen when playing under Australian head coaches averaged 28.74 and struck at 130.97 runs per 100 balls, which isn't far from the mean figures of overseas batsmen in the IPL over the 11 years of the competition.  Bowling-wise, Australian bowlers when employed by Australian coaches cost 29.35 runs per wicket, and went for 7.87 runs per over, and the runs per wicket figure was worse than overseas bowler figures for all years except 2014.  

Summarising, there is very little statistical reason as to why Australian players are favoured more by Australian coaches, with Australian players overall looking virtually identical to the average overseas player.

Is there another reason why coaches and franchises could be biased towards Australian players?

Earlier on in this piece, I mentioned recency bias, and this also manifests itself with the selection of Australian players, with the IPL conveniently coming after the Big Bash in the international calendar.  The human brain tends to trick itself that more notable events happen more often than they actually do, so a one-off world-beating performance is often overvalued by those who don't use data to assess players.

So - if a player performs well in the Big Bash, it is logical that they would be at the forefront of IPL franchises thoughts with regard to immediate recruitment.

This year, after the conclusion of the league phase of the IPL, Australian players when batting scored 22.23 runs per wicket at a strike rate of 133.91 - very mediocre numbers indeed - but the same Australian players in the 2018 Big Bash scored 34.32 runs per wicket at a strike rate of 147.60, vastly improved numbers.

To a lesser extent, Australian bowlers had the same issue, recording 29.85 runs per wicket and 8.94 runs per over so far in the IPL, but the same players improved this to 26.10 runs per wicket and 8.09 runs per over in the Big Bash.

Across both batting and bowling, Australian players performed considerably worse in this season of the IPL than in the Big Bash in the recent 2017-2018 season.

This was also prevalent in the 2017 IPL, compared to the 2016-17 Big Bash.  Australian bowlers who played in both events (Nathan Coulter-Nile and Steve Smith did not play in the Big Bash) did considerably better in the Big Bash (average 24.46, economy 7.61) to the IPL (30.46 and 8.46 respectively), although Australian batsmen performed marginally better in the 2017 IPL compared to the Big Bash.

However, we can see that there is a very strong theme of underperformance from Australian players in the IPL, compared to their Big Bash data, and it would be extremely unrealistic for franchises, fans, and the media alike to expect Australian players to be able to reproduce the Big Bash performances in the IPL.  Certainly, when assessing data, it became extremely apparent that many Australian pace bowlers find it tougher on Indian wickets than Australian ones, and generally, the batsmen struggle more against quality spin in the subcontinent, as opposed to in Australia.  

Despite this, when asked why he felt Glenn Maxwell underperformed in this year's IPL, Delhi Daredevils coach Ricky Ponting was quoted as saying 'I wish I knew why' - perhaps Ponting is yet to understand this particular phenomenon, although I will add that my expectations of Maxwell in this year's IPL were also considerably above his eventual performance, and it would be a reasonable argument to suggest that his under-performance was simply variance.

Glenn Maxwell under-performed in this year's IPL...

Concluding, it would appear that decision makers at IPL franchises appear to be a little seduced by recent Big Bash performances currently, which would be a major mistake.  The skill-sets required to succeed in the Big Bash and the IPL are very different indeed and the IPL is a considerably higher-quality competition.  Being able to assess the difference in standards between various franchise leagues is critical, and is a major part of our algorithms.

If this article has given you insight into the data that Sports Analytics Advantage can offer cricket teams around the world in formulating draft or auction plans, selection strategies or tactics, please feel free to chat to us at sportsanalyticsadvantage@gmail.com.


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