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: r.butler@ucc.ie

david.butler@ucc.ie

2

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.

3

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.

4

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 31

st 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)

5

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

6

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.

7

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 1

st 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 twenty-

three 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.

8

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

9

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 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

2000 - 2004 8.31 7.61 8.30 8.08 8.50 8.27 8.73 8.56 8.60 8.64 8.19 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).

10

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 U-

21 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.

11

Table 3: Birth-date Distribution and U-21 level and Kolmogorov-Smirnov Test

Kolmogorov-Smirnov Test

Country 1 2 3 4 5 6 7 8 9 10 11 12 P value

Austria 8 2 8 4 2 9 4 5 6 7 7 0

Belarus 5 4 4 1 1 4 2 3 1 4 1 1 P < 0.01

Belgium 10 5 8 8 5 4 2 4 3 5 10 2

Bosnia Herzegovina 7 3 5 5 3 4 3 3 3 3 1 3 P < 0.01

Bulgaria 7 5 4 2 4 3 6 3 4 3 6 1 P < 0.1

Croatia 5 10 5 6 5 7 7 6 4 1 1 3 P < 0.01

Cyprus 2 3 2 2 2 1 1 5 4 2 3 2

Czech Rep 7 9 13 8 11 4 5 7 6 2 4 3 P < 0.01

Denmark 8 7 5 7 7 3 5 2 3 4 1 1 P < 0.01

England 6 4 6 6 6 2 2 4 5 5 5 1

Finland 4 2 6 4 1 4 3 2 5 2 2 3 P < 0.05

France 6 4 7 5 8 3 10 5 4 8 1 2

Germany 5 8 10 6 1 4 3 3 6 4 1 2 P < 0.01

Greece 6 2 7 4 1 7 3 2 8 1 2 3 P < 0.01

Hungary 7 5 9 7 3 4 5 3 4 3 3 5 P < 0.01

Ireland 9 9 4 5 10 4 2 8 6 2 4 3 P < 0.01

Israel 10 7 6 8 7 2 6 5 2 7 1 3 P < 0.01

Italy 8 6 1 4 6 7 4 2 4 1 2 1 P < 0.01

Latvia 8 10 6 3 6 3 2 3 1 4 1 1 P < 0.01

Lithuania 6 8 7 9 5 1 6 6 5 3 2 7 P < 0.01

Macedonia 3 5 2 8 2 1 4 5 1 1 2 3 P < 0.1

Northern Ireland 10 4 3 6 8 3 9 2 2 3 4 3

Netherlands 6 4 6 7 1 3 3 6 2 0 2 3 P < 0.01

Norway 6 9 7 4 6 3 7 2 1 5 2 4 P < 0.01

Poland 10 8 6 10 8 8 8 9 7 2 5 6 P < 0.01

Portugal 7 7 6 4 7 3 1 2 3 4 5 5 P < 0.01

Romania 5 10 5 3 4 9 3 3 3 3 1 3 P < 0.01

Russia 13 11 6 7 4 5 5 8 7 3 1 1 P < 0.01

Scotland 7 2 8 5 6 2 6 6 7 1 4 2 P < 0.05

Serbia 4 1 6 7 3 4 4 6 6 2 3 1

Slovakia 7 11 5 3 1 4 4 0 2 6 1 1 P < 0.05

Slovenia 9 9 1 4 4 2 8 3 4 2 3 2 P < 0.05

Spain 9 11 4 4 5 6 5 2 2 1 3 2 P < 0.01

Sweden 6 4 9 1 3 5 3 3 4 2 2 2 P < 0.01

Switzerland 5 7 4 6 3 3 7 7 3 3 6 3

Turkey 18 10 4 8 5 5 10 8 4 2 1 3 P < 0.01

Ukraine 8 2 9 8 9 6 3 10 10 5 5 1

Wales 7 5 3 4 0 1 5 2 0 5 5 9

Total 274 233 217 203 173 153 176 165 152 121 113 101 P < 0.01

Month of Birth

12

Figure 2 Quarterly Birth-Date Distribution of Irish U-21 Footballers 2007-2009

Quarterly Birth Distribution

22

19

16

9

0

5

10

15

20

25

Jan - Mar Apr - Jun Jul - Sep Oct - Dec

No

. o

f P

lay

ers

Figure 3 Quarterly Birth Distribution of Irish U-21 Footballers 1981-1990

Quarterly Birth Distribution

21

13

10

6

0

5

10

15

20

25

Aug - Oct Nov - Jan Feb - Apr May - Jul

No

. o

f P

lay

ers

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

13

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.

14

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

15

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 cut-

off 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.

16

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 non-

competitive 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.

17

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.

18

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