Modelling home advantage in the Summer Olympic Games

Abstract

Home advantage in team games is well proven and the influence of the crowd upon officials' decisions has been identified as a plausible cause. The aim of this study was to assess the significance of home advantage for five event groups selected from the Summer Olympic Games between 1896 and 1996, and put home advantage in team games in context with other sports. The five event groups were athletics and weightlifting (predominantly objectively judged), boxing and gymnastics (predominantly subjectively judged) and team games (involving subjective decisions). The proportion of points won was analysed as a binomial response variable using generalized linear interactive modelling. Preliminary exploration of the data highlighted the need to control for the proportion of competitors entered and to split the analysis pre- and post-war. Highly significant home advantage was found in event groups that were either subjectively judged or rely on subjective decisions. In contrast, little or no home advantage (and even away advantage) was observed for the two objectively judged groups. Officiating system was vital to both the existence and extent of home advantage. Our findings suggest that crowd noise has a greater influence upon officials' decisions than players' performances, as events with greater officiating input enjoyed significantly greater home advantage.

Full text

Modelling home advantage in the Summer Olympic
Games
N.J. BALMER,
1
A.M. NEVILL
2
* and A.M. WILLIAMS
1
1
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, 15–21 Webster Street, Liverpool
L3 2ET and
2
School of Sport, Performing Arts and Leisure, University of Wolverhampton, Walsall Campus, Gorway
Road, Walsall WS1 3BD, UK
Accepted 24 February 2003
Home advantage in team games is well proven and the influence of the crowd upon officials’ decisions has been
identified as a plausible cause. The aim of this study was to assess the significance of home advantage for five
event groups selected from the Summer Olympic Games between 1896 and 1996, and put home advantage in
team games in context with other sports. The five event groups were athletics and weightlifting (predominantly
objectively judged), boxing and gymnastics (predominantly subjectively judged) and team games (involving
subjective decisions). The proportion of points won was analysed as a binomial response variable using
generalized linear interactive modelling. Preliminary exploration of the data highlighted the need to control for
the proportion of competitors entered and to split the analysis pre- and post-war. Highly significant home
advantage was found in event groups that were either subjectively judged or rely on subjective decisions. In
contrast, little or no home advantage (and even away advantage) was observed for the two objectively judged
groups. Officiating system was vital to both the existence and extent of home advantage. Our findings suggest
that crowd noise has a greater influence upon officials’ decisions than players’ performances, as events with
greater officiating input enjoyed significantly greater home advantage.
Keywords: crowd noise, officiating, subjective judging.
Introduction
Baron Pierre de Courbertin proposed the revival of the
Olympic Games in 1892, with the modern Olympic
Games beginning in Athens in 1896. Since then, the
Olympic Games has grown in number of events,
number of competing nations, number of competitors
and number of home competitors (although not
proportionally to all competitors). There are now more
than 40 times more competitors than in 1896, 14 times
more nations competing and nearly seven times more
events (43 in Athens vs 300 in Sydney). Although such
growth has led to concerns about gigantism (Walle-
chinsky, 2000), the Olympic Games has evolved into
perhaps the world’s foremost sporting event, and
provides a rare opportunity to examine differences in
home advantage between sports.
The existence of home advantage in major team
sports has been well established (for a review, see
Nevill and Holder, 1999). Examples include baseball
(Adams and Kupper, 1994), football (Pollard, 1986;
Nevill et al ., 1996), ice hockey (Agnew and Carron,
1994) and basketball (Moore and Brylinsky, 1993).
Courneya and Carron (199 2) proposed four possible
factors that are thought to account for home
advantage: travel factors, learning/familiarity, rule
factors and crowd factors. The present study focuses
primarily upon crowd factors and specifically the
influence of officials upon home advantage. For major
league baseball, Schwartz and Barsky (1977) identi-
fied increasing home advantage with crowd density,
while also attempting to control for team quality.
Subsequently, Nevill et al. (1996) demonstrated
frequency of penalties and sendings-off to favour the
home side, this discrepa ncy increasing with crowd
size. The authors concluded that the crowd might
either influence away players to play more recklessly
or affect the match officials’ decisions in favour of the
home side. There is now growing experimental
support for the latter hypothesis, with Nevill et al.
(1999, 2002a) showing the pr esence of crowd noise
to result in an imbalance of refereeing decisions in
favour of the home side.
* Author to whom all correspondence should be addressed.
e-mail: a.m.nevill@wlv.ac.uk
Journal of Sports Sciences, 2003, 21, 469–478
Journal of Sports Sciences ISSN 0264-0414 print/ISSN 1466-447X online
#
2003 Taylor & Francis Ltd
DOI: 10.1080/0264041031000101890

The prevalence of home advantage in both individual
sport and unbalanced competition is less clear. Some
evidence of home advantage has been identified in cross-
country running (McCutcheon, 1984), wrestling (Gay-
ton and Langevin, 1992) and World Cup alpine skiing
(Bray and Carron, 1993). In contrast, once quality of
athlete had been accounted for, home advantage was not
found to be a major influence on performance in
individual ‘grand slam’ tennis or ‘major’ golf tourna-
ments (Nevill et al., 1997). Holder and Nevill (1997)
confirmed these findings, suggesting that any apparent
home advantage is mainly an artefact of selection
procedures that favour increased entry of lower ranked
home competitors. The authors suggested that lack of
home advantage could be due to both objective scoring
systems and relatively little subjective input from
officials. Multi-event com petition such as the Olympic
Games allows examination and comparison of home
advantage between team and individual events, as well
as between events relying on differing scoring systems.
Previous research on home advantage in the Winter
Olympic Games (Balmer et al., 2001) has shown home
advantage to vary between events, with a significantly
greater advantage for disciplines in which officials
directly judge outcome. It is suggested that officials in
such sports (e.g. figure skating, freestyle skiing) may be
scoring home competitors disproportionately highly.
There is extensive evidence of officiating bias in
subjectively judged sports. Most of this evidence relates
to specific nationalistic or political bias, rather than a
more general home advantage. Nationalistic and/or
political bias has been demonstrated for a range of
subjectively judged events, including Olympic diving
(Park and Werthner, 1977), figure skating (Seltzer and
Glass, 1991) and gymnastics (An sorge and Scheer,
1988; Whissell et al., 1993). With the exception of
Balmer et al. (2001), who provided some evidence, it is
unclear whether the officiating bias observed in
subjectively judged sports extends to home advantage.
Several recent studies have examined performance in
the Olympic Games (e.g. Lozano et al., 2002; Morton,
2002; Nevill and Stead, 2003). All of these studies
examined performance at a nation level, reclassifying
success while controlling for gross national product and
population size (Lozano et al ., 2002), gross domestic
product and population size (Morton, 2002) and gross
national produc t alone (Nevill and Stead, 2003).
Adjusted indices of success produced dramatic changes
in ranking (compared with observed medal tables), with
Eastern European and island nations fairing particularly
well (Morton, 2002) and Cuba finishing top by a clear
margin (Morton, 2002; Nevill and Stead, 2003).
Although these three studies did not formally consider
home advantage, it was acknow ledged as a potential
influence (e.g. Morton, 2002), though evidently the
authors’ mai n conclusion (regarding Cuba’s perfo r-
mance) remains unaffected, since Cuba has never
hosted the Olympic Games. Clarke (2000) examined
home adva ntage in the Summer Olympic Games at a
nation level (across all events). Home nations were
shown to win approximately three times more medals in
home Olympics (compared with away) and, interest-
ingly, approximately two times more in Olympic Games
either side of their home Olympics. Clarke’s (2000)
primary aim was to assess Australia’s upcoming Sydney
2000 performance; although competitor participation
was discussed (as an influential factor in 1956) it was
not controlled for, as the paper was concerned with
predicting performance rather than explaining home
advantage. Indeed, Clarke (2000) was particularly
successful in this respect, as Australia’s predicted
success (of approximately 20 gold medals and 60
medals in total) was remarkably similar to their
observed medal tallies (16 gold medals and 58 medals
in total).
As in tennis and golf tournaments (Nevill et al.,
1997), team/competitor quality is also a major con-
sideration in the Olympic Games, given the highly
variable medal winning potential of host nations. In
Summer Olympic Games competition, for example, the
United States has won nearly 50 times more medals
than Mexico, even though both have been host nations.
Assessing home advantage must, therefore, involve only
a comparison of home and away performances of the
same nation or team. Previous research has highlighted
team quality as a likely influence, with ‘superior’ teams
tending to exhibit greater home advantage (Schwartz
and Barsky, 197 7), although some authors have made
reservations regarding the classification of quality
(Madrigal and James, 1999). While earlier examples
concerned team games, in which an assessment of the
quality of home and away teams can be fairly easily
made, Olympic competition typically involves many
competitors with a diverse range of abilities, creating
some difficul ty in formally assessing quality. Madrigal
and James (1999) proposed that a proportion of this
‘team quality effect’ may be due to superior teams
enjoying larger or denser and more supportive audi-
ences, although this is not the case for Summer
Olympic Games, as success is not related to large home
crowds. The year of the Olympic Games is more
significant for spectator att endance, as numbers simply
increase over time. For Olympic competition, stronger
nations’ dominance in a given event would severely
reduce weaker host nations’ opportunities for home
advantage. Similarly, stronger nations, with more
competitors capable of winning medals, should be able
to produce more consistent home advantage. Evidently,
then, team quality must be considered to correctly
measure home advantage.
470 Balmer et al.

The aim of the present study was to compare home
advantage between groups of events with varying styles
of officiating. Realization of this aim would put the
consistent home advantage observed in team games in
context alongside both objectively and subjectively
judged individual competition. We hypothesized that
significant home advantage would be observed in
subjectively judged events (gymnastics, boxing) in
which the potential for biased officiating is at its greatest
(Ansorge and Scheer, 1988). We also hypothesized that
significant home advantage would be observed for team
games, in which the crowd may have an influence upon
subjective decisions made by officials (Nevill et al.,
1999, 2002a). In contrast, we hypothesized that events
such as athletics and weightlifting, which have pre-
dominantly objective scoring and little input from
officials, would sho w no home advantage.
Methods
Establishing unbiased home advantage
Inclusions and exclusions
Given the vast amount of Summer Olympic Ga mes
data, a subset of event groups was chosen, made up of
track and field athletics, gymnastics, team games,
boxing and weightlifting. The rationale for the choice
of events is presented in the next subsection.
Assessment of home advantage concerns only
nations who have hosted an Olympic Games (hosting
nations) with intra-nation comparison (home vs away
by nation) being central to a fair assessment. The
inclusion of a large number of weaker non-hosting
nations as away data would simply lead to unrealis-
tically large home advantage. To produce the max-
imum number of hosting nations, only male data
were analysed, as females typically did not compete
until 1928 and, in many cases, much later (prohibit-
ing a thorough pre-Second World War analysis).
Having no data before 1928 alone exclu des all data
for Greece, France, Belgium and Holland, while the
omission of women’s hockey (first played in 1980) or
basketball (first played in 197 6) would result in
significant loss of data.
Additionally, if a given hosting nation has neither
won home nor away in an event, at any Olympic
Games, they were exclu ded. This resulted in a
differing number of hosting nations between events,
both as a result of which Olympic Games each event
was held at and hosting nation performance. A single
medal won, home or away, qualifies a hosting nation
for inclusion in the analysis, classifying them as a
successful hosting nat ion for a given event or group
of events.
Selection of events
Event groups were chosen on the basis of longevity (i.e.
how many Olympic Games events have been contested)
and, most importantly, to allow contrasts between
officiating style. Officials have little or no input in
weightlifting or athletics. In contrast, they decide most
outcomes in boxing and all outcomes in gymnastics. In
team games, although the outcome is decided by goals,
points or baskets, officials make many subjective
decisions. The following groupings were included:
1. Track and field athletics were included as they form
the focal point of modern Olympic Games, as well
as a comprehensive and continuous source of data.
Athletics as a whole contributes 12 of the 16
individual events contested at all Olympic Games
(Greenberg, 2000). Most importantly, events have
objectively measurable outcomes and little subjec -
tive input from officials. As a result of this, track
and field athletics should have little or no home
advantage assuming our research hypothesis about
subjective decisions le ading to home advantage is
correct.
2. Weightlifting is also an almost entirely objective
discipline. Outcom e is generally decided by an
aggregate measure of weight lifted in two or three
disciplines, which have changed on several occa-
sions over time (notably the abolition of single-
handed lifts in 1928). Although judges adjudicate
on the success of each lift, it is assumed that their
input is minimal, with most decisions clear-cut.
Moreover, any ambiguity was further reduced when
the ‘press’ component was removed in 1976 owing
to judging difficulty (Greenberg, 2000). Given its
predominantly objective officiating, weightlifting
should again have little or no home advantage.
3. For gymnastics, judge s have a large subjective input
and directly assess performance. Ansorge and
Scheer (1988) claimed that the ‘effects of biased
officiating are potentially most dramatic in sports in
which the officials actually score the points through
judging the performance of competitors with some
combination of objective and subjective criteria’ (p.
103). Gymnastics provides an example of such
artistic events and should exhibit highly significant
home advantage.
4. Historically, boxing has generated the most con-
troversy of any Olympic sport, including such
connected events as attacks on officials, sit-down
protests and full-scale riots. Much of this contro-
versy has focused upon the five ringside judges and
referee. Indeed, recent measures (since Barcelona
1992) have included banning officials from cocktail
parties and the administration of daily alcohol tests
471Modelling home advantage in the Summer Olympic Games

to ensure they are ‘out of reach’ of influence from
national associations and their officials (W allechins-
ky, 2000). Despite such concerns, little research has
addressed possible inflated home advantage in
boxing. Although a small proportion of boxing
matches are decided by knockout, most Olympic
bouts rely on the subjective assessment of judges
(85.95% of Olympic bouts; Lyberg, 1999c). Given
this subjective judging, boxing should display highly
significant home advantage.
5. Olympic team games have an objective scoring
system (e.g. goals, baskets), although officials
have substantial subjective input during matches.
Home advantage for major team games is well
known (Nevill and Holder, 1999), although it has
not been put into context alongside other major
individual sports. Given the proven influence of
crowd noise upon referees in an experimental
setting (Nevill et al., 1999, 2002a), team games
should be associated with significant home ad-
vantage, although perhaps not as much as artistic
event groups, where judge s directly decide out-
come.
Points and maximum points
Performance was measured using a simple points
system, with 3 points allocated for a gold medal, 2
points for silver and 1 point for bronze. A fair
estimation of performance requires not only points
scored, but also a consideration of the number of points
available. Points were considered as a proportion of
maximum points available, this maximum varying with
event. In most team games or events (e.g. football,
hockey, 46100 m) the maximum is 3 points (i.e. a
single gold), as only one team may be entered.
Elsewhere, the maximum is typically 6 points, as three
or more competitors of the same nationality could win
gold, silver and bronze (6 points) in a given event and
Olympic Games.
Both points and maximum points were combined for
each event group (defined in the previous subsection).
Combined maxim um points also considered number of
competitors or teams, so they never exceeded the
number of points achievable by the number of
competitors or teams entered. The result is a sum of
points for all relevant events, for each Olympic Games
at which the events were contested. Event groups and
number of constituent events or weight categories are
presented in Table 1. Each observation is a proportion
for a given country, in a given event group and Olympic
Games (e.g. Germany won 11 of 48 boxing points at the
1936 Olympic Games). A nation was removed if it had
never contested the events or had never won a point
(home or away) in a given event group. All data were
obtained from the Olympic museum, Lausanne (Ly-
berg, 1999a,b,c,d,e,f,g,h,i). The results from Sydney
2000 were not included, since although medal winning
performance was avai lable, detailed partici pation fig-
ures were only available up to 1996.
Response variable
The response or dependent variable was the number of
points won by each nation as a ratio of the maximum
number of points available.
Explanatory variables
Home versus away
A binary home versus away indicator variable was
entered to allow assessment of the difference between
home and away performance.
Proportion of competitors or teams competing
The number of competitors or teams for each nation,
entered as a proportion of the total competitors or
teams, was included as a covariate likely to influence the
proportion of points won. Most pre-Second World War
Table 1. Event groups included in the analysis and number of constituent events
No. of events/
Observations in analysis (n)
No. of Olympic
Event group weight divisions Dates competed Pre-war Post-war Games
Track and field 25 1896–1996 71 144 23
Gymnastics 8 1896–1996 32 86 23
Weightlifting 10 1896, 1904, 1920–1996 25 115 20
Boxing 12 1904–1908, 1920–1996 29 142 20
Team games 5 1900–1996 44 103 22
Total 201 590
472 Balmer et al.

Olympic Games had few limits on the maximum
number of competitors, leading to inflated home team
sizes, or even additional teams in some early team
games. At the 1904 St. Louis Olympic Games, the host
nation entered two of a total of three competing football
teams (Wallechinsky, 2000). Even after the instigation
of maxima, many nations used the opportunity of a
home Olympic Games to reach the maximum when
otherwise further competitors at considerable cost
would not have been worthwhile. Evidently further
competitors at home would enhance the given host
nation’s ability to win medals (however slightly). To
reach an unbiased home advantage, a competitor
(competitor or team) covariate indicating the number
of competitors or teams entered by each nation in each
event group was included in the analysis.
This covariate was equal to the number of competi-
tors or teams divided by the total number for all nations
(i.e. the proport ion of competitors entered by each
‘hosting nation’, in each event or event group, at each
Olympic Games). Using this value rather than raw
number of competitors or teams accounts for changing
(generally growing) competitor or team participation
over time. This covariate will be referred to as
‘proportion of competitors’ in the analyses.
Host nation
Evidently, stronger host nations win more points and
may enjoy greater home advantage (e.g. Schwartz and
Barsky, 1977; Madrigal and James, 1999). Considera-
tion of differences between host nations as a repeated-
measures ‘within-subject’ factor (‘host’) allows differ-
ences in nation quality to be evaluated and accounted
for.
Pre-war/post-war differences
Differences over time exist both in the number of
competitors entered (especially home competitors) and
number of nations entering. Generally, after 1936,
restrictions were placed upon the number of competi-
tors entering, preventing vast numbers of home
competitors. An increased number of away nations
has also increased competition and may further reduce
home advantage. For this reason, separate analyses
were conducted pre- and post-war to allow for
differences in the proportion of competitors covariate.
The full rationale for this split is explained in the
Analysis section below.
Event group/officiating style
Consideration of the above variables allows both
accurate (unbiased) measurement of home advantage
in each event group and a comparison between groups
with different officiating style s. A five-category event
group factor was included in the analys is to highlight
differences in home advantage between groups (home/
away 6 event group interaction). Analysis was then
split by event group to examine absolute home
advantage for each group.
Changing nations
Two major medal-winning nations that have also hosted
Summer Olympic Games have seen considerable
changes in composition. First, Germany split into East
and West Germany after the Secon d World War, before
re-unifying in time for the 1992 Olympic Games.
Similarly, the Soviet Union collapsed before the 1992
Olympic Games (though a unified team competed in
1992). For simplicity, Germany is defined as West
Germany between 1952 and 1988 (Federal Republic of
Germany from 1968 on wards), although it should be
noted that Germany did enter a combin ed team on
three occasions within this period (1956–1964). After
the collapse of the Soviet Union, Russia is defined as
Russia and not former constituents of the Soviet Union.
We attempt to control for changes in the proportio n of
total athletes or teams entered (and subsequent success)
as a result of these changes (and of boycotts) by using
the proportion of competitors or teams as a covariate.
Analysis
The proportion of medals won by each nation was
analysed using two separate methods. First, traditional
analysis of covariance (ANCOVA) was used, with
measurements relating to the proportion of competitors
entered as a covariate. The general linear model used
assumes normality. However, the response variables
consisting of proportions of points (of total points)
resulted in predictable departures from normality due
to many especially large or small proportions (Zar,
1998). An arcsine transformation (Winer, 1972) to
stabilize variances and produce a more acceptable
normal distribution failed to significantly impro ve
deviations from normality in either the pre-war or
post-war analyses. Preliminary exploration of the data
also highlighted the need to split the analysis pre- and
post-war. This was mainly a result of post-war
competitor restrictions leading to a far less influential
‘proportion of competitors’ covariate, with a markedly
different slope (see Fig. 1).
Proportions of points won by each nation were
analysed as a binomial response variable (e.g. if a
nation won a silver medal in the 100 m athletics final, 2
of 6 points would be allocated to that nation for that
Olympic Games) using generalized linear interactive
473Modelling home advantage in the Summer Olympic Games

modelling (GLIM; Aitkin et al., 1989; Nevill et al.,
2002b). Although proportion of points won is not
strictly a binomial proportion (as it is not generated
from repeated yes/no responses), it is a discrete
distribution with an upper bound (whi ch differed with
event, Olympic Games and number of competitors
entered). In such a case, the binomial distribution
provides the most accurate approximation (rather than
the Poisson distribution where there exists no upper
bound). Rather than assuming the response variable has
a linear function of the covariates with an approximate
normal error, GLIM is able to assess the effect of all the
explanatory variables on the proportion of points won
assuming the exact binomial error distribution (r points
from a possible n). Separate GLIM analyses were
performed on the pre- and post-war data because of
differing ‘proportion of competitors’ covariates. Ana-
lyses were then split by event group both pre- and post-
war.
Results
Pre-war
Fitting the covariate of ‘proportion of competitors’, the
main effects of ‘host’, ‘event group’ and ‘home vs away’
plus the interaction between ‘event group’ and ‘home vs
away’ term explained a loss in deviance of 71628.9 with
17 degrees of freedom (P 50.0001). When we at-
tempted to remove the interaction term, the covariate or
any of the main effects from the model, the increase in
deviance was too large in all cases (P 50.01). Conse-
quently, all terms were retained in the final pre-war
model describing the proportion of points won by the
eight ‘hosting’ nations. The unadjusted and adjusted
proportions of points won (obtained by calculating the
mean intercepts for proportion of points won having
fitted the covariate ‘proportion of competitors’) by
hosting nations pre-war are presented in Figs 2 and 3,
respectively. All error bars in the figures denote the
standard error of the estimate.
Five simplified models were then fitted for each event
group, with the single ‘proportion of competitors’
covariate and main effects ‘host’ and ‘home vs away’.
This allowed absolute measurement of home advantage
for each group. Table 2 presents the direction (home
advantage/away advantage) and significance (change in
scaled deviance as a result of removal from final model)
of the facto r ‘home vs away’ for both pre- and post-war
analyses.
Fig. 1. Proportion of competitors entered versus percentage
of points won, for each Olympic Games, nation and event
group. O, pre-war; 6, post-war.
Fig. 2. Percentage of points (+standard error of the esti-
mate) won by all successful hosting nations pre-war.
,
home; &, away.
Fig. 3. Adjusted percentage of points (+standard error of the
estimate) won by all successful hosting nations pre-war.
,
home; &, away.
474 Balmer et al.

With the factor ‘host’ and covariate ‘proportion of
competitors’ entered, no home advantage was found for
‘track and field’ , ‘weightlifting’ or ‘boxing’. In contrast,
‘gymnastics’ yielded significant home advantage
(w
2
1
= 5.24, P = 0.022), as did ‘team games’
(w
2
1
= 19.38, P 50.001). For each event group, as with
the global analysis, increase in deviance was too large to
remove either ‘host’ or ‘proportion of competitors’,
confirming the need to retain them in each pre-war
model.
Post-war
Adopting the same methodological approach to analys-
ing the pre-war results, the covariate of ‘proportion of
competitors’, the main effects of ‘host’, ‘event group’
and ‘home vs away ’ were fitted, plus the interaction
between ‘event group’ and ‘home vs away’, to explain
the proportion of points won by the 12 hosting nations.
These terms explained a loss in devia nce of 72657.1
with 21 degrees of freedom (P 50.0001). As with the
pre-war analysis, when we tried to remove the interac-
tion term, the covariate or any of the main effects from
the model, the increase in deviance was too large in all
cases (P 50.01). All terms were retained in the final
post-war model describing the proportion of points won
by the 12 ‘hosting’ nations. The unadjusted and
adjusted (for proportion of competitors) proportions
of points won by hosting nations post-war are presented
in Figs 4 and 5, respectively.
Separate models were fitted for each event group,
using an identical procedure to that of the pre-war
analysis. As for the pre-war analyses, Table 2 presents
the direction (home advantage/away advantage) and
significance ( change in scaled deviance as a result of
removal from final model) of the factor ‘home vs away’.
As with the pre-war analysis, ‘track and field’ yielded
no home advantage. Interestingly, once ‘proportion of
competitors’ had been accounted for, ‘weightlifting’
Table 2. Extent and direction of home advantage for each of the five event groups pre-war (Pre) and post-war (Post)
Direction of advantage
Change in scaled
deviance, w
2
Degrees of freedom P-value
Event group Pre Post Pre Post Pre Post Pre Post
Track and field Away Home 0.22 0.20 1 1 0.64 0.66
Gymnastics Home Home 5.24 25.23 1 1 0.022 5 0.001
Weightlifting Home Away 1.46 6.21 1 1 0.23 0.013
Boxing Home Home 2.47 42.92 1 1 0.12 5 0.001
Team games Home Home 19.38 9.99 1 1 5 0.001 0.0015
Fig. 4. Percentage of points (+standard error of the esti-
mate) won by all successful hosting nations post-war.
,
home; &, away.
Fig. 5. Adjusted percentage of points (+standard error of the
estimate) won by all successful hosting nations post-war.
,
home; &, away.
475Modelling home advantage in the Summer Olympic Games

now exhibited significant away advantage (w
2
1
= 6.21,
P = 0.013). Meanwhile, a large significant home ad-
vantage was observed for ‘gymnastics’ (w
2
1
= 25.2,
P 50.001), ‘team games’ (w
2
1
= 9.99, P = 0.0015) and
‘boxing’ (w
2
1
= 42. 9, P 50.001). As with previous
analyses, increase in deviance was too large to remove
either ‘host’ or ‘proportion of competitors’, confirming
their importance in the model.
Discussion
The present study had two objectives. The first was to
assess the significance of home advantage in a subset of
Summer Olympic Gam es event groups, while identify-
ing and controlling for confounding factors. The
second was to examine differences in home advantage
between groups of events relying on differing officiating
styles. We hypothesized that sports requiring subjective
judgement (boxing, gymnastics) or subjective decisions
(team games) woul d yield highly significant home
advantage. In contrast, little or no home advantage
was expected for sports for which officiating is less overt
or predominantly an objective process (track and field,
weightlifting).
In both the pre-war and post-war analyses, overall
home advantage was found to be significant, high-
lighted by the large change in deviance when attempting
to remove the ‘home vs away’ main effect. The
‘proportion of competitors’ covariate was also found
to be highly influential both pre- and post-war,
indicating the importance of proportion of competitors
or teams to successful performance. Controlling for this
covariate proved central to a fair measure of home
advantage, highlighted by the marked difference be-
tween unadjusted (Figs 2 and 4) and adjusted
performance (Figs 3 and 5). A similar measure of
participation could prove valuable in the further
development of al lometric models of Olympic perfor-
mance (e.g. Lozano et al., 2002; Morton 2002; Nevill
and Stead, 2003).
Significantly different slopes for the ‘proportion of
competitors’ covariate illustrated the need to split the
analysis pre- and post-war, as shown by Fig. 1.
Similarly, significant differences were noted between
‘host’ nations’ point-winning performances. Entry of a
nation main effect accounted for a large proportion of
variance (due to substantial differences between na-
tions), confirming ‘team quality’ concerns of previous
research (e.g. Schwartz and Barsky, 1977; Holder and
Nevill, 1997; Nevill et al., 1997; Madrigal and James,
1999). The success of different nations is also likely to
have been influenced by numerous boycotts. These
include Spain, Switzerland, Egypt, Iraq and Lebanon in
1956, various Africa n nations in 1976, the United
States in 1980 and the Soviet Union at the following
Olympic Games. These boycotts, particularly the final
two, clearly enhanced the performance of host nations
and, therefore, increased home advantage. Fitting the
‘proportion of competitors’ covariate attempted to
control for such boycotts (by modelling increases in
proportion of competitors), alth ough it is unlikely that it
completely accounted for the quality of competitors
lost. When we assessed differences in home advantage
between event groups, the conclusions remained
unaffected. However, analysis at the level of nations
(e.g. attempting to predict a particular nation’s future
medal-winning performance; e.g. Clarke, 2000) would
require further consideration of boycotts and quality of
competitor.
The most important finding was the significance of
the home/away6event group interaction, both pre-
and post-war. Subsequent analysis for each individual
event group revealed the source of this significant
interaction term. Pre-war, the significant home/
away6group interaction term was a result of a small
(non-significant) away advantage in the two objec-
tively judged groups, compared with significantly
greater positive home advantage for gymnastics and
substantial home advantage for team games. Post-war,
when competitor participation had stabilized to some
extent due to restrictions, the home/away6gro up
interaction was a result of significantly greater home
advantage in event groups that are either subjectively
judged (gymnastics, boxing) or rely on subjective
decisions (team games). Home advantage for these
three groups was significantly greater than that of the
two objectively judged groups (track and field,
weightlifting) once we had controlled for the propor-
tion of competitors/teams.
Objectively judged groups showed no home advan-
tage either pre- or post-war (Figs 3 and 5) and, in the
case of post-war weightlifting, even showed some
indication of away advantage. This may be explained
by nations which have never hosted the Olympic Ga mes
beginning to enter participants in weightlifting and
becoming increasingly strong as time progresses.
Notable examples include Bulgaria, Romania and
China, none of whom featured in men’s weight lifting
medals tables between 1948 and 1968. Bulgaria then
topped the table with six medals in 1972 and won six
again in 1976. Similarly, Romania and China occupied
the top two weightlifting table spots in 1984, winning
14 of 30 medals between them. An increasing number
of strong away nations may reduce home nations’
chances of winning medals compared with earlier away
Olympic Games in which such nations were not present
or competitive.
With respect to subjectively judged events, our results
confirm previous Winter Olympic Gam es findings
476 Balmer et al.

(Balmer et al., 2001) that such disciplines enjoy
significantly greater home advantage than events with
little officiating input. Evid ently, this officiating com-
ponent is vital for home advantage in individual sports.
This could explain why significant home advantage has
been observed in wrestlin g (Gayton and Langevin,
1992), even at high school level, but not international
tennis or golf (Holder and Nevill, 1997; Nevill et al .,
1997). It would appear that the potential for biased
officiating in subjectively judged events predicted by
Ansorge and Scheer (1988) is confirmed in terms of
home advantage.
As hypothesized, team games demonstrated highly
significant home advantage both pre- and post-war,
although the size of this imbalance was surprisingly
large. Team games demonstrated by far the largest
home advantage pre-war and highly signifi cant home
advantage post-war (Table 2). Pre-war, a lack of
competitive away teams and failure to complete ly
account for additional home teams (‘proportion of
competitors’) may partially explain this imbalance.
Post-war, following instigation of entry restrictions,
home advantage remains highly significant, although
somewhat less so than for the subjectively judged
groups.
Previous research has highlighted crowd factors as a
dominant cause of home advantage. Crowds are able to
influence players and officials to alter performance to
favour the home side or nation (Pollard 1986; Nevill et
al., 1996 ). Competitors in all of the event groups enjoy
consistently la rge and vocal crowds. If these crowds
were able to influence competitors’ performance, home
advantage would be observed for all event groups,
which was not the case. Far greater home advantage in
the three event groups with substantial officiating input
supports the latter hypothesis, that the crowd is able to
influence officials to favour the home side. Experi-
mental research has provided support for a crowd
influence upon officials in association football (Nevill et
al., 1999, 2002a). However, while an imba lance of
decisions was identified, this was not quantified in
terms of home advantage. The results of the present
study suggest that the imbalance observed with crowd
noise in football translates to a sizeable home advan-
tage, significantly larger than that for objectively judged
events and comparable to that for subjectively judged
events.
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