### Is home advantage in boxing because of biased judging?

Here's still another study from the Home Field Advantage issue of "Journal of Sports Sciences," this one called "Do judges enhance home advantage in European championship boxing?"

In boxing, if one fighter does not knock out his opponent, the winner of the fight is determined solely by the opinions of judges – that is, entirely subjectively. If the "home field advantage" in sports is partly the result of biased officials, you would expect that boxing would show a very large HFA, compared to similar sports where judges are not as large a factor.

In the paper, authors N. J. Balmer, A. M. Nevill, and A. M. Lane look at the issue by, in effect, comparing boxing to itself. Specifically, they compare fights in which there was a knockout, to fights in which the judges decided the winner. Since knockouts are independent of the judges' scoring decisions, the authors argue that if HFA is larger in decisions than in knockouts, this represents evidence of judge bias.

And, after a bunch of logistic regressions that adjust for boxer quality, that's indeed what they found.

"For equally matched boxers, expected probability of a home win was 0.57 for knockouts, 0.66 for technical knockouts, and 0.74 for points decisions. ... We suggest that interventions should be designed to inform judges to counter home advantage effects."

But there's a big problem getting from the numbers to the conclusion. Specifically, there is no reason why you should expect the HFA in knockouts to equal the HFA in decisions.

For instance: suppose that when a boxer knows he's losing on points, late in a fight, he knows the only way he can win is to knock out his opponent. So he takes lots of chances, hoping to land a lucky punch for the knockout. The opponent who's leading, on the other hand, concentrates only on defense, hoping to protect himself from a knockout to win the fight on points.

If that scenario is the cause of most actual knockouts, then it's the *weaker* boxer, not the stronger, who wins the most knockouts. It's perfectly possible that the HFA might even be *negative* on fights that ended in knockouts. And that would be the case whether or not the judges were biased in the other 90% of the fights.

In general, selectively sampling games based on *after-the-fact* criteria can give you almost any HFA at all.

For instance, suppose you want to find a category of hockey games in which the intrinsic home winning percentage is over .900. Here's one, based on a simplified model of hockey:

Suppose team A and team B are equal. Overall, they each get 30 shots on goal per game, with a shooting percentage of .100 overall. But that's an average of the home team actually shooting .120, and the visiting team shooting .080 (for an expected score of 3.6 to 2.4).

I ran a simulation of this game, and, counting a tie has half a win, the home team has an overall winning percentage of around .695.

But, you can easily show, using the binomial theorem, that the home team will have a winning percentage of .906 in games in which either team scores exactly eight goals.

---------------------------------

How often will each team score exactly 8 goals? By the binomial theorem, for the home team, it's

p(home) = .120^8 * .880^22 * C(30,8) = 1/66

For the visiting team, it's

p(road) = .080^8 * .920^22 * C(30,8) = 1/637

1/66 divided by (1/66 + 1/637) equals .906. (This ignores 8-8 ties, which I didn't bother accounting for.)

----------------------------------

And so:

-- in hockey games as a whole, the HFA is .195.

-- in hockey games where one team scores a "knockout" of at least 8 goals, the HFA is .406.

Compare this to what the boxing study found:

-- in boxing matches by a decision, the HFA is .24.

-- in boxing matches by a knockout, the HFA is .06.

In the hockey case, the results are due to the structure of the game, not any bias on the part of the referees. And the same could be true in the boxing case. Which means, that, unfortunately, the conclusion that boxing judges are biased is not supported by the evidence.

Labels: boxing, home field advantage

## 1 Comments:

看房子,買房子,建商自售,自售,台北新成屋,台北豪宅,新成屋,豪宅,美髮儀器,美髮,儀器,髮型,EMBA,MBA,學位,EMBA,專業認證,認證課程,博士學位,DBA,PHD,在職進修,碩士學位,推廣教育,DBA,進修課程,碩士學位,網路廣告,關鍵字廣告,關鍵字,課程介紹,學分班,文憑,牛樟芝,段木,牛樟菇,日式料理, 台北居酒屋,日本料理,結婚,婚宴場地,推車飲茶,港式點心,尾牙春酒,台北住宿,國內訂房,台北HOTEL,台北婚宴,飯店優惠,台北結婚,場地,住宿,訂房,HOTEL,飯店,造型系列,學位,SEO,婚宴,捷運,學區,美髮,儀器,髮型,看房子,買房子,建商自售,自售,房子,捷運,學區,台北新成屋,台北豪宅,新成屋,豪宅,學位,碩士學位,進修,在職進修, 課程,教育,學位,證照,mba,文憑,學分班,台北住宿,國內訂房,台北HOTEL,台北婚宴,飯店優惠,住宿,訂房,HOTEL,飯店,婚宴,台北住宿,國內訂房,台北HOTEL,台北婚宴,飯店優惠,住宿,訂房,HOTEL,飯店,婚宴,台北住宿,國內訂房,台北HOTEL,台北婚宴,飯店優惠,住宿,訂房,HOTEL,飯店,婚宴,結婚,婚宴場地,推車飲茶,港式點心,尾牙春酒,台北結婚,場地,結婚,場地,推車飲茶,港式點心,尾牙春酒,台北結婚,婚宴場地,結婚,婚宴場地,推車飲茶,港式點心,尾牙春酒,台北結婚,場地,居酒屋,燒烤,美髮,儀器,髮型,美髮,儀器,髮型,美髮,儀器,髮型,美髮,儀器,髮型,小套房,小套房,進修,在職進修,留學,證照,MBA,EMBA,留學,MBA,EMBA,留學,進修,在職進修,牛樟芝,段木,牛樟菇,關鍵字排名,網路行銷,PMP,在職專班,研究所在職專班,碩士在職專班,PMP,證照,在職專班,研究所在職專班,碩士在職專班,SEO,廣告,關鍵字,關鍵字排名,網路行銷,網頁設計,網站設計,網站排名,搜尋引擎,網路廣告,SEO,廣告,關鍵字,關鍵字排名,網路行銷,網頁設計,網站設計,網站排名,搜尋引擎,網路廣告,SEO,廣告,關鍵字,關鍵字排名,網路行銷,網頁設計,網站設計,網站排名,搜尋引擎,網路廣告,SEO,廣告,關鍵字,關鍵字排名,網路行銷,網頁設計,網站設計,網站排名,搜尋引擎,網路廣告,EMBA,MBA,PMP,在職進修,專案管理,出國留學,EMBA,MBA,PMP,在職進修,專案管理,出國留學,EMBA,MBA,PMP,在職進修,專案管理,出國留學,婚宴,婚宴,婚宴,婚宴,漢高資訊,漢高資訊,比利時,比利時聯合商學院,宜蘭民宿,台東民宿,澎湖民宿,墾丁民宿,花蓮民宿,SEO,找工作,汽車旅館,阿里山,日月潭,阿里山民宿,東森購物,momo購物台,pc home購物,購物漢高資訊,漢高資訊,在職進修,漢高資訊,在職進修,住宿,住宿,整形,造型,室內設計,室內設計,漢高資訊,在職進修,漢高資訊,在職進修,住宿,美容,室內設計,在職進修,羅志祥,周杰倫,五月天,住宿,住宿,整形,整形,室內設計,室內設計,比利時聯合商學院,在職進修,比利時聯合商學院,在職進修,漢高資訊,找工作,找工作,找工作,找工作,找工作,蔡依林,林志玲

Post a Comment

## Links to this post:

Create a Link

<< Home