Homing in on the Home Advantage

19 Dec

A recent piece on ESPNCricinfo analyses the DRS data and argues that cricket should do away with neutral umpires. I reanalyzed the data.

If a game is officiated by a home umpire, we expect the following:

  1. Hosts will appeal less often as they are likely to be happier with the decision in the first place
  2. When visitors appeal a decision, their success rate should be higher than the hosts. Visitors are appealing against an unfavorable call—a visiting player was unfairly given out or they felt the host player was unfairly given not out. And we expect the visitors to get more bad calls.

When analyzing success rate, I think it is best to ignore appeals that are struck down because they defer to the umpire’s call. Umpire’s call generally applies to LBW decisions, and especially two aspects of the LBW decision: 1. whether the ball was pitching in line, 2. whether it was hitting the wickets. To take a recent example, in the second test of the 2021 Ashes series, Lyon got a wicket when the impact was ‘umpire’s call’ and Stuard Broad was denied a wicket for the same reason.

Ollie Robinson Unsuccessfully Challenging the LBW Decision

Stuart Broad Unsuccessfully Challenging the Not-LBW Decision

With the preliminaries over, let’s get to the data covered in the article. Table 1 provides some summary statistics of the outcomes of DRS. As is clear, the visiting team appealed the umpire’s decision far more often than the home team: 303 vs. 264. Put another way, the visiting team lodged nearly one more appeal per test than the home team. So how often did the appeals succeed? In line with our hypothesis, the home team appeals were upheld less often (24%) than visiting team’s appeals (29%).

Table 1. Review Outcomes Under Home Umpires. 41 Tests. July 2020–Nov. 2021.

REVIEWER TYPETOTAL PLAYER REVIEWSSTRUCK DOWN (%)UMPIRE’S CALL (STRUCK DOWN) (%)UPHELD (%)
HOME BATTING9639 (40%)25 (26%)32 (34%)
HOME BOWLING168108 (64%)29 (18%)31 (18%)
VISITOR BATTING14758 (39%)25 (17%)64 (44%)
VISITOR BOWLING15697 (62%)34 (22%)25 (16%)
Data From ESPNCricinfo

It could be the case that these results are a consequence of something to do with host vs. visitor than home umpires. For instance, hosts win a lot, and that generally means that they will bowl for shorter periods of time and bat for longer periods of time. We account for this by comparing outcomes under neutral umpires. The article has data on the same. There, you see that the visiting team makes fewer appeals (198) than the home team (214). And the visiting team’s success rate in appeals is slightly lower (29%) than the home team’s rate (30%).

p.s.

At the bottom of the article is another table that breaks down reviews by host country:

HOST COUNTRYTESTSUMPIRESREVIEWSHOSTS’ SUCCESS (%)VISITORS’ SUCCESS (%)
ENGLAND13AG WHARF, MA GOUGH*, RA KETTLEBOROUGH*, RK ILLINGWORTH*19022/85 (26%)32/105 (30%)
NEW ZEALAND4CB GAFFANEY*, CM BROWN, WR KNIGHTS413/17 (18%)5/24 (21%)
AUSTRALIA4BNJ OXENFORD, P WILSON, PR REIFFEL*555/30 (17%)6/25 (24%)
SOUTH AFRICA2AT HOLDSTOCK, M ERASMUS*202/10 (20%)3/10 (30%)
SRI LANKA6HDPK DHARMASENA*, RSA PALLIYAGURUGE859/42 (21%)13/43 (30%)
PAKISTAN2AHSAN RAZA, ALEEM DAR*270/11 (0%)6/16 (38%)
INDIA5AK CHAUDHARY, NITIN MENON*, VK SHARMA879/40 (23%)11/47 (23%)
WEST INDIES6GO BRATHWAITE, JS WILSON*9413/50 (26%)13/44 (29%)
Data from ESPNCricinfo

But the data doesn’t match the one in the table above. For one, the number of tests considered is 42 than 41. For two, and perhaps relatedly, the total number of reviews is 599 than 567. To be comprehensive, let’s do the same calculations as above. The visiting team appeals more (314) than the host team (285). The host team success rate is 22% (63/285), and the visiting team success rate is 28% (89/314). If you were to do a statistical test for success rates:

 prop.test(x = c(63, 89), n = c(285, 314))

        2-sample test for equality of proportions with continuity correction

data:  c(63, 89) out of c(285, 314)
X-squared = 2.7501, df = 1, p-value = 0.09725
alternative hypothesis: two.sided
95 percent confidence interval:
 -0.13505623  0.01028251
sample estimates:
   prop 1    prop 2 
0.2210526 0.2834395 

Sense and Selection

11 Dec

The following essay is by Chaste. The article was written in early 2018.

———

I will discuss the confounding selection strategies of England, India, and South Africa in the recently finished series. I won’t talk about minutiae like whether Vince’s technique is suited to Australian conditions or whether Rohit Sharma with his current form or Rahane with his overseas quality should have started the series. This is about basic common sense and basic cricketing sense, which a sharp 10-year-old has, and which the selectors appear to lack. Part 1 talks about England’s Ashes selection; Part 2 is about India and South Africa’s selections in the recent Test series.

Part 1

In the recent Ashes, were it not for Cook’s 244 in Melbourne, England would have lived up to their billing as 5-nil candidates. The 5-nil billing was unusual since England was 3rd in the ICC rankings on 105, and Australia was 5th on 97. So how did we get to the expectation of a whitewash?

The English team selection appeared almost geared to maximize the chances of a whitewash. The basics of selection are to identify certain spots and to select enough good options for the uncertain spots. The certain spots were clear: 1 wicketkeeper in Bairstow, two batsmen in Root and Cook, and four bowler/all-rounders in Anderson, Broad, Stokes, and Ali. In addition, Stoneman and Woakes were half-certain spots—sure to play at least 2-3 matches.

The selectors’ job was clear: make enough good selections to address the remaining 2.5 batting spots and the 0.5 bowling spot. And what did they do? They selected three batsmen (Ballance, Vince, and Malan) for the 2.5 batting spots and three bowlers (Ball, Overton, and Crane) for the 0.5 bowling spots.

Brilliant! This left England’s batting no margin for error. There was no backup opener, in effect locking in Stoneman for all five matches. Vince had a county average last season of 33, not much higher than Kyle Abbott, a tail-ender and Vince’s mate at Hampshire, who averaged 30. Let us also not forget that England’s primary innovation in the last couple of years is to become a very attractive batting side that can’t play swing, spin, pace, or bounce. True, the fragility of the English batting is hardly the selectors’ fault. It’s due primarily to England’s ground rating system, where the groundsmen get perfect scores for preparing perfect roads. But it is still the selectors’ job to address this fragility in their selections. Given that Australian wickets don’t turn much and that the open positions were 2, 3, and 5, you would have expected England to take a couple of spare openers (Robson and Roy, for example) who could have batted in any of those positions. Instead, they took only Ballance.

And what were the bowling selections for which England’s batting options were sacrificed? Neither of the two pace backups provided any variety to the attack. There is simply nothing that Ball and Overton can do that is better or different than Woakes. Plunkett, suited to Australian conditions, was ignored. Wood was ignored for the bizarre reason that he might not last the entire series. But wait, there was no chance that Ball or Overton (let alone both) would have played all five matches. Crane was selected on the chance that he might play in one match. Besides, Wood would not have been a good replacement for Woakes in more than 2–3 matches, so demanding his fitness for all five matches was pointless. As if all this absurdity wasn’t enough, when Stokes was ruled out, they replaced a batting all-rounder with another quick bowler/drinks carrier (Finn).

And what were the bowling selections for which England’s batting options were sacrificed? Neither of the two pace backups provided any variety to the attack. There is simply nothing that Ball and Overton can do that is better or different than Woakes. Plunkett, suited to Australian conditions, was ignored. Wood was ignored for the bizarre reason that he might not last the entire series. But wait, there was no chance that Ball or Overton (let alone both) would have played all five matches. Crane was selected on the chance that he might play in one match. Besides, Wood would not have been a good replacement for Woakes in more than 2–3 matches, so demanding his fitness for all five matches was pointless. As if all this absurdity wasn’t enough, when Stokes was ruled out, they replaced a batting all-rounder with another quick bowler/drinks carrier (Finn).

So what made the English selectors adopt strategies that maximized the chances of a whitewash? In recent years, England has adopted a policy of giving every batsman at least a 5–7 test run before the drop: plenty of chances to shine/rope to hang yourself. While the policy makes sense for experienced players, its merits for new batsmen are dubious. I don’t know that an excruciatingly prolonged examination of Roy’s form or Keaton Jennings’ technique during last summer helped those players. To say nothing of burdening the rest of the team with passengers. It is the kind of policy that only world-beating sides can afford. But England stuck to it even though they were looking at a 5-nil drubbing. Since each batsman had at least five tests left in their allotted “chance to fail or shine quota,” England didn’t pick alternate batsmen.

Part 2

There is a basic difference between batsmen and bowlers. Batsmen must stop batting as soon as they get out. Hence, when you increase the number of batsmen in your side, you are likely to get a higher score. Bowlers, on the other hand, can bowl until they drop down dead. Thus, in theory, bowling only Marshall and Garner would help you bowl the opposition out most cheaply. You add bowlers (Holding and Croft, for example) only to provide:

  • Adequate rest so that all bowlers can function properly.
  • Necessary variations: types of pace, bound, swing, spin, etc.

Thus, your best combination is always the minimum number of bowlers (4) and the maximum number of batsmen (6 + keeper). Even if your side is blessed with a great all-rounder like Imran Khan or Keith Miller, you still go with six specialist batsmen. If you are looking to your 5th bowler for wickets, you have selected your top 4 bowlers poorly. It’s very helpful to have a batting all-rounder who can bowl well enough to rest the four main bowlers without releasing pressure. A great example is Mitchell Marsh in the recent Ashes, even though he didn’t take a single wicket all series.

There are a few cases where a 5th bowler/bowling all-rounder can be useful:

  • There is simply no chance of your team losing on a wicket full of runs. The only possibilities are a draining draw or going for a win on the 5th day.
  • The specialist batsmen on your bench don’t bat any better than your all-rounders. Recent England sides are a good example.

Far from having one or both of the above, this series … 

  • Was the first in test history with three or more matches in which every match saw the fall of 40 wickets.
  • Saw an average innings total of 218: South Africa’s average was 230, and India’s was 206.
  • saw fewer than 350 overs (less than four full days of play) in its longest match.

Predictably then, the 5th bowlers were largely a waste. Ashwin and Maharaj bowled 18.1 overs in match 1, and Phehlukwayo and Pandya bowled 18 overs in match 3. That’s right: they averaged less than five overs per innings over these two matches: a few balls more than the T20 quota. And it is for this reason that India dropped Rahane / Rohit Sharma, and South Africa dropped Bavuma.

Of course, we know that the 5th bowler is meant to signal aggression, positive intent, and other such buzzwords. But to an intelligent opponent, it only signals that you are clueless about test cricket. It is akin to Kohli repeatedly getting out to a 6th stump line in England, which shows a lack of understanding of the basics of test cricket. It is understandable that with an unrelenting diet of different forms of cricket, young cricketers like Kohli may not understand the basics specific to each form. But we have a right to expect better from the selectors and coaches.

About Chaste

Chaste is a consumer in the addiction economy. He spends half his time on Cricinfo and the other half hating himself for spending half his time on Cricinfo.