The Relative Age Effect in Under 21 Association Football: An Irish and European
Perspective
David Butler, Robbie Butler & Meadhbh Sherman*
* Department of Economics, University College Cork, Cork, Republic of Ireland.
Key Words: Relative Age Effects, Under 21, Association Football.
Tel: 00 353 21 490 2434
Email: [email protected]
[email protected]
Abstract
This paper considers the existence of a relative age effect in association football at Under-21
level across thirty-eight European countries from May 2007 – June 2009. The paper confirms
the existence of a relative age effect with a selection bias towards players born earlier in the
calendar year. Furthermore, by conducting a natural experiment evidence of a shifting bias is
observed for the case of U-21 football in Ireland between the years 1980 and 2009. In order
to reduce the impact of relative age effects, this paper recommends alterations to cut-off dates
at an earlier stage in underage football, the reframing of the playing environment at underage
level and effective education of mentors when identifying talented footballers to play at an
elite level. Such steps could reduce age effects and result in increased equality of opportunity
for all underage players seeking to represent their country and elite level.
2
Introduction
This research examines the persistence of relative age effects in association football. It
examines male under twenty-one (U-21) international squads across Europe from May 2007
– September 2009. Male U-21 players were identified as an appropriate age group due to
their selection to represent at an elite level, their common succession to the status of senior
player and because of their lengthy experience within a youth structure that grouped players
chronologically within a uniform age cut-off date. The competitive nature and high regard
associated with U-21 level throughout international football ensures commitment to
achieving success across countries; guaranteeing a true assessment of a country’s underage
talent.
For elite representative teams to achieve sporting success, a process of talent identification
and development is required to seek and prolong advantage over rivals. Due to chronological
age groupings in association football, whereby a selection year is formed confining player
eligibility to a specific year, distinguishing and nurturing such talent has been subject to
relative age effects (Verhulst, 1992; Brewer, Balsom & Davis 1995; Helsen, Van Winckel &
Williams, 2005). The presence of an age effect continues the likelihood that player
identification and subsequent development produces elite performers born in the earliest
quarter of the selection year. Physiological, cognitive and social advantages consistently arise
between older and younger children when assembled in groups (Malina, 1994) enhancing the
chances of success for older children. These advantages produce a systematic bias in the
talent identification process, skewing birth date distributions of elite players.
The research attempts to not only demonstrate the persistent of a relative age effect in
association but also the existence of a shifting bias once the rules regarding cut-off dates at
underage level are changes. Such a shift is demonstrated using the natural experiment of
association football in Ireland pre and post 1997. This finding along with others in the paper
poses serious questions to the development of underage football across Europe. This paper
seeks to address these questions and offers recommendation to football authorities as to how
to minimise the problem of relative age effects. Section 2 that follows critiques the literature
on relative age effects. Section 3 outlines the methodology used to test the relative age effect
among elite footballers. Section 4 presents the results, while section 5 offers
recommendations to football policy-makers to reduce relative age effects. Section 6
concludes the paper.
3
The relevance of age effect studies to football should offer an insight to the limits of
structuring the sport by chronological age, a model of organising youth football that
ironically seeks to ensure fairness by adopting an age cut-off date. As of 1997 the football
governing body, FIFA, altered the cut-off date to January 1st, thus establishing a new
eligibility guideline for international competitions; to qualify for a particular age group, a
player must be born between the 1st of January and the 31st of December of that year. The
existence of such rules across all sports at underage level as inspired the application of age
effect studies to a not just football but many other sports1. Importantly, studies considering
the alteration of selection dates have hence shown a shifting age bias to the first months of
the new selection period (Brewer et al., 1995; Musch & Hay, 1999, Cobley, Schorer & Baker,
2008).
Central to the failings of categorising children within a chronological age group is the
presence of consistent age bands throughout a youth structure. A child born in January will
persistently have an eleven month age advantage over December born children for the
duration of their status as a youth or ‘underage’ footballer. Consistent relative age research
confirming linkages between age and academic achievement served as a precursor to
applying the concept to sporting environs2 (Shearer, 1967). It is important to note, that
disparities which exist between the application of the relative age concept with regard to
pedagogic attainment and success in a sporting realm; whilst school attendance is compulsory
partaking in sport is a voluntary act (Musch & Hay, 1999). Evidence of converging school
performance of older and younger children within a year group (Hauck & Finch, 1993;
Kinard & Reinherz, 1986) demonstrates, over time, how compulsory attendance combats an
age effect. The voluntary nature of sport does not allow for the indulgence.
Physiological and anthropometric advantages possessed by relatively older children allow
them to be selected more often due to physical capabilities that are necessary for the
attainment of success. Additional benefits of greater physical maturity include selection for
1
Football studies have been conducetd by Barnsley, Thompson & Legault (1992), Verhulst (1992), Dudink
(1994), Baxter-Jones, Helms, Maffull, Baines-Preece & Preece, (1995), Brewer, Balsom & Davis (1995),
Helsen, Starkes, Van Winckel (1998), Musch & Hay (1999), Simmon & Paull (2001), Helsen, Van Winckel &
Williams (2005) and popularised by Gladwell (2008) and Syed (2010). Furthermore, studies have been carried
out on American football (Daniel & Janssen, 1987), cricket (Edwards, 1994), ice hockey (Grondin, Deshaies &
Nault, 1984; Barnsley & Thompson, 1988; Sherar, Baxter-Jones, Faulkner & Russell, 2007) and baseball
(Thompson, Barnsley & Stebelsky 1991; Stanaway & Hines, 1995).
2
Research as to how season of birth impacts an individual has a extensive history, see Huntington (1938)
4
higher standard teams, facilitating greater practice levels, improved mentoring and
supplementary playing time (Barnsley et al., 1992). With physicality needed to meet the
demands of football weaker children can be isolated within a competitive environment.
Physical advantages remain central to the occurrence of a relative age effect (Cobley, Schorer
& Baker, 2010). From the basis of considerable biological maturity and initial success a set of
behaviours is evoked from both players’ and mentors that reinforce an already imprecise
definition of talent, initialising a month of birth bias.
Outlined by Dudink (1994) as a “cascade effect”, selection bias given physiological and
anthropometric advantages of the early maturing child increases the prospect of selection on
future occasions. The Pygmalion effect (Rosenthal & Jacobson, 1968; Rosenthal., 1974)
emerges as a cognitive mechanism that reinforces an age effect. Less biologically advanced
children, who do not favour selection, encounter aggravation due to less playing time,
provoking potential dropout (Sharp, 1995). Advanced biological maturity that allows
comparably superior skills such as agility or coordination complements on-going selection,
acceding to a child forming a positive psychological state that originated from initial success.
(Bandura, 1977). As older children establish dominance within a team through witnessed
ability greater perceived ability, physique, or social status are increasingly likely to continue
within organised sport, while those who perceive their talent as weak would be likely
candidates to dropout (Harter’s, 1981). Acknowledged by Helsen et al (2005), a youth
footballer’s perception of success or failure assists the reinforcement of age effects. Older
children who take advantage of their own maturity and achieve success explain the result in
causal terms, (Weiner, 1986). A child experiencing success on the field of play and constant
selection for youth teams could likely justify their success in terms of their performance, a
level of ability that the child would consider above that of their peers who do not warrant
selection.
The role of mentors as gate keepers in the process of benchmarking ‘talent’ is significant.
Mentoring perceptions that are biased by transitory growth differences at an early stage in a
child’s development facilitates the division of a pool of talent into ‘skill hierarchies’ (Lander
& Fine, 1996). An attempt to cultivate talent through a particular culture has been subject to
much review in a sociological context (Carlson, 1988, 1993; Cote, 1999; Salmela, 1996).
Social interactions and the extent of one’s exposure to the game require consideration when
evaluating a mentor’s diverging perception of talent. Agreement between mentors and
5
selected players facilitates a social concord that is required for nurturing talent (Carlson,
1993). With competitive structures, relative age effects continue to arise as competitive forces
establish a desire to play from team members (Musch & Grondin, 2001). Acquiring and
maintaining a selection place, encourages a competitive culture. If a mentor’s objectives are
in harmony with that of the child a synchronised ambition can incite the occurrence of an age
effect.
Criticisms of the relative age effects in football are rare but concentrate on linkages between
seasonality of birth and demographics. Seasonality of birth and its connection to sociocultural
status in addition to biological or environmental influences is considered by Musch and Hay
(1999). Associating opportunity to a particular personality and climatic variables that are a
consequence of which season one is born in appears tenuous, especially given that no
homogenous personality or psychological profile can be identified for an elite organised
sportsperson (Morris, 2000). Seasonal and climatic explanations suggested are not practical
criticisms as players born in the same seasonal conditions may fall into different
chronological age bands (Musch & Grondin, 2001). Alternative interpretations point to the
exact nature of what is being measured and to what factors are the greatest contributors to an
age effect occurring; is an ‘age effect’ being measured which takes account of all variables
possessed by an older child or are studies actually measuring ‘physique effects’ and the
benefits of maturing earlier. The identification of a shifting periodicity of age bias in line with
a cut-off dates (Brewer et al., 1995, Musch & Hay, 1999), suggests the potency of such
criticisms appears weak.
6
Materials & Methods
Birth dates were sourced from official national association’s websites and player club
websites (where available). European countries ranked eighty or above in the FIFA world
rankings, as of June 2009, were considered.3 U-21 players born on or after the 1st of January
1986 were included, ensuring their eligibility for the 2009 finals as per UEFA European U-21
Championship regulation 17.2, providing a uniform age cut-off date for each country. Players
selected for U-21 squads in the eight to ten qualification matches and European
Championship play-off ties between May 2007 and October 2008 were included in the
sample. Squads for friendly ties played between February 2009 and June 2009 were also
included. All qualification match and playoff ties squads were obtained from UEFA records.
A total of 2081 observations are recorded for thirty-eight countries (see Table 1). To test the
shifting periodicity of the bias at U-21 level for Ireland data was collected for international
players between the years 1981 to 1990 from the Football Association of Ireland. Data was
available for the u-21 squads in the years 1981, 1985, 1987 and 1990. All players in this
sample participated in youth football under a cut-off date of August 1st. A total of fifty
observations were collected.
To ensure the validity of acquired dates of birth two further online databases were consulted
allowing triangulation of observations. Where players’ dates of birth consistently differed
between all sources, the player’s date of birth was considered inaccessible. A total of twentythree missing birth dates existed from the population of 2104 European U-21 players, leaving
a sample group of 2081 players. Small samples were obtained for Bosnia Herzegovina,
Cyprus and Macedonia as only qualification campaigns were considered. A customary
induction of ‘new’ players occurred for the majority of countries under inspection after the
qualification campaign allowing sizeable data collection. The introduction of a ‘new’ squad
of players was not witnessed for every country, a noteworthy example was Belarus.
Data acquisition difficulties did occur; inconsistent amounts of fixtures, language barriers and
absent squad information did not allow for a standardised end date to be established for the
countries sampled. For these reasons the closing date of when the sample group of players
was concluded differs between countries. In the cases of Bosnia Herzegovina, Cyprus and
Macedonia only qualification campaigns, concluding in September 2008, are considered,
3
Belarus was deemed as having an elite status following their qualification to the 2009 UEFA U21
Championships and was included in the sample.
7
while the Bulgarian sample included the full qualification campaign but only selected
friendly matches; these restrictions were owing to both limited official data sources and
translation difficulties of the countries in question at the time of research. Finally, players that
were born after the 1st of January 1986 that did not represent their country at a U-21 level
given their appearance at a senior level between May 2007 and June 2009 were included in
the sample. As these players performed on the highest international football stage, their elite
status was assumed.
Table 1: Number of Players Used by Country: May 2007- June 2009.
Country
Number of Observations
Poland
87
Czech Republic
79
Turkey
78
Ukraine
76
Russia
71
Belgium, Ireland
66
Lithuania
65
Israel
64
France
63
Austria
62
Croatia
60
Hungary
58
Northern Ireland, Switzerland
57
Norway, Scotland
56
Portugal, Spain
54
Denmark, Germany
53
England, Romania
52
Slovenia
51
Bulgaria, Latvia
48
Serbia
47
Greece, Italy, Wales
46
Slovakia
45
Sweden
44
Bosnia Herzegovina, Netherlands
43
Finland
38
Macedonia
37
Belarus
31
Cyprus
29
Total
2081
8
In line with other studies, players were grouped in accordance by month of birth. “Month 1”
corresponds to a January birth, “month 2” February and so on, with a December birth
recorded as “month 12”. Observed birth-dates for each country are recorded by month, with
expected the expected birth-date distribution based on the average monthly birth rate in
England and Wales from 2000 to 2004 inclusive. This is appropriate given similar birth
distribution across other European countries (Cowgill, 1965). Table 2 presents this
distribution. It can be observed that very little variance in births occurs from month-to-month.
Table 2: Average Percentage Monthly Births in England & Wales 2000 – 2004.
Years
2000 - 2004
Jan
8.31
Feb
7.61
Mar
8.30
Apr
8.08
May
8.50
Jun
8.27
Jul
8.73
Aug
8.56
Sep
8.60
Oct
8.64
Nov
8.19
Dec
8.22
Kolmogorov-Smirnov one-sample test are used to measure differences in expected monthly
birth-dates based on the England and Wales data and observed distribution of players
representing their country at U-21 level (Siegel & Castellan (1988) and Helsen et al, (2005).
9
Results
The birth-date distributions for U-21 national teams for the thirty-eight associations along
with the Kolmogorov-Smirnov test are presented in Table 3. For the sample of thirty-eight
countries, twenty-three report significant effects at the 1% confidence level. A further four
report significant effects at the 5% level, while two countries report significant effects at the
10% confidence level. Admittedly, four ten countries the null hypothesis cannot be rejected
and it is assumed no significant presence of a relative age effect at U-21 level. The reasons
for this are unknown and are left to future research. The overall sample reports significant
effects at the 1% confidence level. Players born in the first quarter of the year are more
prevalent throughout the sample than those born in later quarters. The first quarter, from
January to March, yields a birth rate 34.7% of players (n= 724), while only 15.9% of elite U21 footballers are born within the final quarter of the selection period (n= 335).
The results from Table 3 pose the questions as to why those born in early months of the year
are more likely to be selected at U-21 level. To eliminate the unlikely chance that those born
in earlier months of the year are simply ‘better’ footballers a natural experiment was
conducted for selection to the Irish U-21 team from 1980 to 2009. As of 1997 the football
governing body, FIFA, altered the cut-off date to January 1st however prior to this change a
cut-off date of the 1st of August was used in Ireland for all underage football competitions
including selection to national teams. To test the shifting periodicity of the bias at U-21 level
data was collected for international players between the years 1981 to 1990. Data was
available for the 1981, 1985, 1987 and 1990 teams. All players in this sample participated in
youth football under a cut-off date of August 1st. This was then compared to the sample of
sixty six players for the 2007 – 2009 period. For both samples a descending quarterly bias
existed. For the 2007 – 2009 sample, the descending quarterly bias existed toward those born
in the early months of the selection year. However for the 1980 -1990, a descending quarterly
bias existed toward those born in the early months of the selection year e.g. biased towards
August, September, October and so on, with May to July the least frequent months for player
births. This natural experiment illustrates that players born earlier in the calendar year are not
naturally ‘better’ players than those born later in the year. Simply shifting the cut-off date
will shift the bias to other parts of the calendar year. Figures 2 and 3 illustrate this shifting
bias for Ireland.
10
Table 3: Birth-date Distribution and U-21 level and Kolmogorov-Smirnov Test
Country
1
2
3
4
Austria
8
2
8
4
Belarus
5
4
4
1
Belgium
10
5
8
8
Bosnia Herzegovina
7
3
5
5
Bulgaria
7
5
4
2
Croatia
5 10
5
6
Cyprus
2
3
2
2
Czech Rep
7
9 13
8
Denmark
8
7
5
7
England
6
4
6
6
Finland
4
2
6
4
France
6
4
7
5
Germany
5
8 10
6
Greece
6
2
7
4
Hungary
7
5
9
7
Ireland
9
9
4
5
Israel
10
7
6
8
Italy
8
6
1
4
Latvia
8 10
6
3
Lithuania
6
8
7
9
Macedonia
3
5
2
8
Northern Ireland
10
4
3
6
Netherlands
6
4
6
7
Norway
6
9
7
4
Poland
10
8
6 10
Portugal
7
7
6
4
Romania
5 10
5
3
Russia
13 11
6
7
Scotland
7
2
8
5
Serbia
4
1
6
7
Slovakia
7 11
5
3
Slovenia
9
9
1
4
Spain
9 11
4
4
Sweden
6
4
9
1
Switzerland
5
7
4
6
Turkey
18 10
4
8
Ukraine
8
2
9
8
Wales
7
5
3
4
Total
274 233 217 203
Kolmogorov-Smirnov Test
Month of Birth
5
6
7
8
9 10 11 12
P value
2
9
4
5
6
7
7
0
1
4
2
3
1
4
1
1
P < 0.01
5
4
2
4
3
5 10
2
3
4
3
3
3
3
1
3
P < 0.01
4
3
6
3
4
3
6
1
P < 0.1
5
7
7
6
4
1
1
3
P < 0.01
2
1
1
5
4
2
3
2
11
4
5
7
6
2
4
3
P < 0.01
7
3
5
2
3
4
1
1
P < 0.01
6
2
2
4
5
5
5
1
1
4
3
2
5
2
2
3
P < 0.05
8
3 10
5
4
8
1
2
1
4
3
3
6
4
1
2
P < 0.01
1
7
3
2
8
1
2
3
P < 0.01
3
4
5
3
4
3
3
5
P < 0.01
10
4
2
8
6
2
4
3
P < 0.01
7
2
6
5
2
7
1
3
P < 0.01
6
7
4
2
4
1
2
1
P < 0.01
6
3
2
3
1
4
1
1
P < 0.01
5
1
6
6
5
3
2
7
P < 0.01
2
1
4
5
1
1
2
3
P < 0.1
8
3
9
2
2
3
4
3
1
3
3
6
2
0
2
3
P < 0.01
6
3
7
2
1
5
2
4
P < 0.01
8
8
8
9
7
2
5
6
P < 0.01
7
3
1
2
3
4
5
5
P < 0.01
4
9
3
3
3
3
1
3
P < 0.01
4
5
5
8
7
3
1
1
P < 0.01
6
2
6
6
7
1
4
2
P < 0.05
3
4
4
6
6
2
3
1
1
4
4
0
2
6
1
1
P < 0.05
4
2
8
3
4
2
3
2
P < 0.05
5
6
5
2
2
1
3
2
P < 0.01
3
5
3
3
4
2
2
2
P < 0.01
3
3
7
7
3
3
6
3
5
5 10
8
4
2
1
3
P < 0.01
9
6
3 10 10
5
5
1
0
1
5
2
0
5
5
9
173 153 176 165 152 121 113 101
P < 0.01
11
Figure 2 Quarterly Birth-Date Distribution of Irish U-21 Footballers 2007-2009
Quarterly Birth Distribution
25
22
19
No. of Players
20
16
15
9
10
5
0
Jan - Mar
Apr - Jun
Jul - Sep
Oct - Dec
Figure 3 Quarterly Birth Distribution of Irish U-21 Footballers 1981-1990
Quarterly Birth Distribution
25
21
No. of Players
20
15
13
10
10
6
5
0
Aug - Oct
Nov - Jan
Feb - Apr
May - Jul
Figure 4 Population Adjusted Quarterly Birth Distribution of Irish U-21s Footballers
Birth distribution in Ireland for the years under analysis provides an approximately even
distribution (CSO, 2011). Using Irish population statistics as a test case one could deduce that
while population statistics on a country by country basis may appear inconsistent, significant
differences between quarterly population statistics would be necessary to qualify a criticism
against the biases discovered. Delorme, Boiche and Raspaud (2010) have raised the concern
of using a methodology that compares national population statistics, favouring a comparison
of nationally licensed players. Comparison of nationally licensed players however only goes
some way to explaining the initialisation of an age effect as no valid reasoning exist to
12
suggest that those born in the first quarter are overtly inclined toward organised football.
Additionally given the variety of sporting contexts such effects have been found in, the
shifting periodicity of the bias and that not every male will participate in organised sport, let
alone organised football, large deviations in national population statistics would be necessary
to qualify a criticism against the concept of relative age bias.
13
Discussion
The findings show a visible asymmetry in birth distributions at a European U-21 level and a
shifting bias when the cut-off date is changed. Footballers born between January and March
are afforded an increased opportunity to achieve selection for an elite representative team. Pre
1997 footballer in Ireland born in August, September and October were afforded a greater
chance of success. The existences of such biases need to be minimised. Firstly, the
competitive setting in which talent is nurtured should be realised for its function of generating
an age effect (Musch & Grondin, 2001). Age effect tendencies will continue if short term
accomplishment remains the primary objective of mentors and players. The format of
contests facilitates such drives as youth competitions model themselves closely to the format
of adult professional leagues. Dual fixtures and league formats allow a competitive mentality
permeate youth football as squads, by virtue of the 'league table’, are geared solely toward
prize-winning. While a league format and dual fixtures may ensure a fairest outcome with
regard to winning, it fosters a competitive culture that provides ample motivation for
physiological advantages to perpetuate as the goal of nurturing talent is overshadowed by one
of achieving success.
The importance of the physical playing environment in establishing an age effect warrants
engagement from both football bodies and academia. The Football Association of Ireland
accepts that organised competitive football matches for children at eleven are conducted
within a full playing pitch. Standard field dimensions, established by FIFA, impose a
minimum pitch length of 90m and minimum width of 45m as a requirement for adult
matches. These dimensions of the playing surface are the lowest possible requisite
measurement and are conducive to utilising physique as factors such as the distance and
height a player can kick a ball, aerial ability and speed are all supported by the natural
playing environment. Physical environments provide stimulus for anthropometric differences
to become an advantage.
Age Structuring
Reconsideration of chronological age bands could be addressed from various perspectives.
Consistently changing cut-off dates or bi-annual age categories at a young age could reduce
age effects (Helsen et al., 2005, Barnsley & Thompson, 1988). These processes could reduce
the range of ages within a particular band, establishing fewer physical differences, thus
providing a possible solution to higher dropout rates at a young age as observed by
14
Petlichkoff (1996). Segregating youths to a greater extent would encourage greater practice
hours and more playing time. If age cut-off dates were sequenced so as the selection
parameters were consistently disrupted, biases against children born in the final quarter of the
selection year could be avoided (Boucher & Halliwell, 1991). Also employing an age quota
strategy may potentially act as a deterrent to producing an age effect within football
(Barnsley and Thompson, 1988). This process requires individual teams to have quotas on
players born in different quarters of the selection year.
Alternative methods founded upon physiological differences have been widely cited as a
means categorising youth footballers, with proposed options including that of shifting toward
a system based on biological age rather than chronological age structuring (Musch &
Grondin, 2001). Arranging players by skeletal age and other physiological traits could
provide a promising means of letting footballers of similar anthropometric classification
compete (Baxter-Jones, Helms, Maffull, Bains-Preece & Preece, 1995). Football associations
that oppose alterations to the selection year due to onerous administrative processes could
alternate cut-off dates for school competitions; by football associations implementing a cutoff date of July 1st for all schools competitions, a feasible mechanism that disrupts age effects
could be adopted whilst maintaining administrative consistency for each organisation.
Mentoring & Education
Focus upon mentoring practices and the role of selectors, especially upon a child’s uptake of
football, is due considerable attention when seeking to negate relative age effects within the
sport. Realigning the function and goals of mentors at each stage of a child’s development
within football is a necessary adjustment in overcoming a co-ordination problem as current
objectives, which can often be geared toward achieving success, should be of greatest
concern at an adult level. Wholesale education of mentors and knowledge of relative age
effects is imperative in furthering football throughout Europe, allowing mentors to take an
important step from understanding to prevention. Providing mentors with the acumen to
know their correct role between given age bands is a crucial task for football associations. A
further solution is to accept the presence of an age effect and thereafter attempt to remedy the
problem through mentoring. The adoption of ‘late maturation’ programs could act as a
mechanism to maintain participation levels and provide an alternative route to elite football
for late developers. A delaying of the selection process forwarded by Baker et al (2010)
flanked by such programs could serve to alleviate the bias.
15
Physical & Social Environments
Talent development implies the concept that players are given an appropriate environment to
learn the game, allowing them realise opportunity through their individual talents (Williams
& O’Reilly 2000). Both the physical environments in which football is played and social
conditions that embrace an unhealthy degree of competition require attention to repudiate
relative age effects that perpetuate in a forum that does not nurture talent fittingly. The
competitive league structure for young children must be addressed to remove a ‘league table’
format that produces winners, losers and exacerbates competitive urges. Shifting not to a noncompetitive match structure but to a system that individual match outcomes do not impact
subsequent ties could move to diminish the intensity of competitiveness at an underage level.
Adjustments to physical environments should accompany changes to fixture organisation. By
removing the incentive to realise success through a strategy that excessively utilises physical
characteristics, mentors should be induced to adopting more balanced tactics. An example of
such an adjustment would be set national guidelines that regulate the playing area and goal
dimensions in accordance to child development.
The flexibility of football, whereby the rules can be adopted to different pitch dimensions and
goal sizes, may offer an opportunity to overcoming the relative age effect by altering the
playing environment. While avid desires to ‘win’ may appear difficult to amend, adapting the
environment in which talent is nurtured could potentially remove the incentive, and
effectiveness of selecting a youth player primarily upon additional maturity or physique.
While this strategy may only lessen age biases, it attempts to transform the incentives of
mentors that consequently must seek a strategy not based purely on the advantages of the
early maturing child. From a technical perspective, the complexity of the physical
environment, especially the field dimensions and goal sizes require enquiry. Whilst at a
young age interaction with the ball appears to be the greatest obstacle to a child, with
progression, physical dimensions and the physique of opponents become an increasingly
visible impediment. Allowing for the evolution of field dimensions and goalpost sizes that
correspond to a child’s age may serve to naturally reduce seasonal bias, fostering talent not
through a utopian removal of competition but through rules that hinder the advantages of
physical attributes yet promote the benefits of skill and technique.
16
Conclusion
Analysing U-21 footballers that were selected to represent national squads between May
2007 and June 2009 a relative age effect was found, with a selection bias towards those born
earlier in the year. This bias is confirmed by econometric testing of the data. The
confirmation of a shifting bias in the case of Ireland, after the synchronisation of the
international cut-off date by FIFA to January 1st of a given year, further supports the
existence of a relative age effect bias. Changes are required to underage football structures to
combat this bias. Alternations are necessary in the segregation of talent at a young age.
Changes are also required to the physical environment in which children play. Finally,
education of mentors is essential if relative age effect biases are to be overcome. While the
first two changes are revolutionary the latter is evolutionary and will take time to manifest
among mentors. These finding pose a challenge to football policymakers today to achieve
higher performance levels and reduce early dropout rates.
Acknowledgments
The authors would like to acknowledge the contribution of Dr. John Considine and Dr.
Geraldine Ryan to this work. Their comment and advice was a source of exceptional
guidance throughout.
17
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