Related unedited note: The relative age effect
Introduction
The term relative age effect (RAE) is used to describe a bias in youth sport ((Bell, J.F., Sykes, E.D. and Vidal, C., 2009. Birthdate Effects: A Review of the Literature from 1990-on. UK: University of Cambridge)) and academia,((Crawford, C., Dearden, L. and Meghir, C., 2007. When you are born matters: The impact of date of birth on child cognitive outcomes in England)) where participation is higher amongst those born earlier than would be expected from the distribution of births. The selection period is either the calendar year, the academic year or the sporting season. ((Kelly, A.L., Côté, J., Hancock, D.J. and Turnnidge, J., 2021. Birth Advantages and Relative Age Effects. _Frontiers in Sports and Active Living_, p.210.))
Malcolm Gladwell’s book Outliers: The Story of Success, popularised the issue in respect of Canadian ice-hockey players, European football players, and US Major League baseball players.
This effect is often associated with the difference in maturity ((Fumarco, L. and Rossi, G., 2016. Long-term Relative Age Effect: Evidence from Italian Football. _source: http://voxeu. org/article/relative-age-effect-over-long-term_)) with age category, skill level and sport context also impacting the risk. Mid to late adolescent, regional to the nation, popular sports seeing the highest risk, and under 11, recreational, unpopular sports seeing the lowest risk. ((Cobley, S., Baker, J., Wattie, N. and McKenna, J., 2009. Annual age-grouping and athlete development. _Sports medicine_, _39_(3), pp.235-256))
The seasonal birth effect is similar but is fundamentally different. Season of birth examines the influence of different prenatal and perinatal seasonal environmental factors like sunlight, temperature, or viral exposure during gestation, that relate to health outcomes. ((BARRY, H., 1961. Season of birth: An epidemiological study in psychiatry. _Archives of General Psychiatry_, _5_(3), pp.292-300)) Whereas the relative age effect shifts with selection dates ((Helsen, W.F., Starkes, J.L. and Van Winckel, J., 2000. Effect of a change in selection year on success in male soccer players. _American Journal of Human Biology: The Official Journal of the Human Biology Association_, _12_(6), pp.729-735)) moving the advantage with the selection period ((Musch, J. and Hay, R., 1999. The relative age effect in soccer: Cross-cultural evidence for a systematic discrimination against children born late in the competition year. _Sociology of sport journal_, _16_(1), pp.54-64)) with influence from social agents. ((Hancock, D.J., Adler, A.L. and Côté, J., 2013. A proposed theoretical model to explain relative age effects in sport. _European journal of sport science_, _13_(6), pp.630-637.)) The children born soon after the cut-off date are typically included, and a child born soon before the cut-off date excluded.
Youth sport participation is often organized into annual age-groups often using the 1st of January as the cut-off but the 1st of September is used in the UK ((Cobley, S., Baker, J., Wattie, N. and McKenna, J., 2009. Annual age-grouping and athlete development. _Sports medicine_, _39_(3), pp.235-256)) like many other locations around the world. ((Wattie, N., Cobley, S. and Baker, J., 2008. Towards a unified understanding of relative age effects. _Journal of sports sciences_, _26_(13), pp.1403-1409))
The declining distribution from the beginning of the year for professional athlete participation has been seen in sports like Football, ((Ashworth, J. and Heyndels, B., 2007. Selection bias and peer effects in team sports: The effect of age grouping on earnings of German soccer players. _Journal of sports Economics_, _8_(4), pp.355-377)) baseball, ((Herring, C.H., Beyer, K.S. and Fukuda, D.H., 2021. Relative Age Effects as Evidence of Selection Bias in Major League Baseball Draftees (2013–2018). _The Journal of Strength & Conditioning Research_, _35_(3), pp.644-651)) basketball, ((Faria, L.O., Bredt, S.D.G.T., Ribeiro, A.I., Galatti, L.R. and Albuquerque, M.R., 2021. Inequality in Brazilian basketball: the birthplace effect. _Revista Brasileira de Cineantropometria & Desempenho Humano_, _23_.)) cricket,((Edwards, S., 1994. Born too late to win?. _Nature_, _370_(6486), pp.186-186.)) gymnastics, ((Baxter-Jones, A.D., 1995. Growth and development of young athletes. _Sports medicine_, _20_(2), pp.59-64.)) handball ((Rubia, A.D.L., Bjørndal, C.T., Sánchez-Molina, J., Yagüe, J.M., Calvo, J.L. and Maroto-Izquierdo, S., 2020. The relationship between the relative age effect and performance among athletes in World Handball Championships. _PloS One_, _15_(3), p.e0230133.)) ice hockey, ((Addona, V. and Yates, P.A., 2010. A closer look at the relative age effect in the National Hockey League. _Journal of Quantitative Analysis in Sports_, _6_(4).)) rugby league, ((Till, K., Cobley, S., Wattie, N., O’hara, J., Cooke, C. and Chapman, C., 2010. The prevalence, influential factors and mechanisms of relative age effects in UK Rugby League. _Scandinavian journal of medicine & science in sports_, _20_(2), pp.320-329.)) running, ((Romann, M. and Cobley, S., 2015. Relative age effects in athletic sprinting and corrective adjustments as a solution for their removal. _PLoS One_, _10_(4), p.e0122988.)) skiing, ((Romann, M. and Fuchslocher, J., 2014. Survival and success of the relatively oldest in Swiss youth skiing competition. _International Journal of Sports Science & Coaching_, _9_(2), pp.347-356.)), swimming, ((Baxter-Jones, A.D., 1995. Growth and development of young athletes. _Sports medicine_, _20_(2), pp.59-64.)) tennis, ((Ulbricht, A., Fernandez-Fernandez, J., Mendez-Villanueva, A. and Ferrauti, A., 2015. The relative age effect and physical fitness characteristics in German male tennis players. _Journal of sports science & medicine_, _14_(3), p.634.)) and the Youth Olympic Games,((Abioye, A.I., Odesanya, M.O., Abioye, A.I. and Ibrahim, N.A., 2015. Physical activity and risk of gastric cancer: a meta-analysis of observational studies. _British journal of sports medicine_, _49_(4), pp.224-229.)) as well as non-physical sports like shooting. ((Delorme, N. and Raspaud, M., 2009. Is there an influence of relative age on participation in non-physical sports activities? The example of shooting sports. _Journal of sports sciences_, _27_(10), pp.1035-1042.))
Impact Factors
The relative age effect is related to the birth date of individuals but is affected by social agents like parents, coaches and athletes through the self-fulfilling prophecy,((Thompson, A.H., Barnsley, R.H. and Stebelsky, G., 1991. “Born to play ball” The relative age effect and major league baseball. _Sociology of Sport Journal_, _8_(2), pp.146-151.)) Pygmalion effect, Galatea effect, and Matthew effect ((Hancock, D.J., Adler, A.L. and Côté, J., 2013. A proposed theoretical model to explain relative age effects in sport. _European journal of sport science_, _13_(6), pp.630-637.)) which can all impact player motivation. ((Harter, S., 1978. Effectance motivation reconsidered. Toward a developmental model. _Human development_, _21_(1), pp.34-64.))
In addition to these social factors, contextual differences change the distribution with decreased effects in female sports,((Abel, E.L., Kruger, M.M. and Pandya, K., 2011. A relative age effect in men’s but not women’s professional baseball: 1943–1954. _Psychological reports_, _109_(1), pp.285-288.))((Romann, M. and Fuchslocher, J., 2014. The need to consider relative age effects in women’s talent development process. _Perceptual and motor skills_, _118_(3), pp.651-662.)) unpopular sports, ((Wattie, N., Baker, J., Cobley, S. and Montelpare, W.J., 2007. A historical examination of relative age effects in Canadian hockey players. _International Journal of Sport Psychology_, _38_(2), pp.178-186.)) at younger ages,((Delorme, N., Chalabaev, A. and Raspaud, M., 2011. Relative age is associated with sport dropout: evidence from youth categories of French basketball. _Scandinavian journal of medicine & science in sports_, _21_(1), pp.120-128.)) individual sports ((Baker, J., Janning, C., Wong, H., Cobley, S. and Schorer, J., 2014. Variations in relative age effects in individual sports: Skiing, figure skating and gymnastics. _European journal of sport science_, _14_(sup1), pp.S183-S190.)) or sports with a lower reliance on body size ((Gil, S.M., Bidaurrazaga-Letona, I., Larruskain, J., Esain, I. and Irazusta, J., 2021. The relative age effect in young athletes: A countywide analysis of 9–14-year-old participants in all competitive sports. _PloS one_, _16_(7), p.e0254687.)) with an expected increased effect in male sports, popular sports, or competitive sports.((Delorme, N., Chalabaev, A. and Raspaud, M., 2011. Relative age is associated with sport dropout: evidence from youth categories of French basketball. _Scandinavian journal of medicine & science in sports_, _21_(1), pp.120-128.)) The sport’s popularity in a geographical or cultural area will also affect the distribution with examples seen in Volleyball, ((Musch, J. and Grondin, S., 2001. Unequal competition as an impediment to personal development: A review of the relative age effect in sport. _Developmental review_, _21_(2), pp.147-167.)) and American football. ((Stanaway, K.B. and Hines, T.M., 1995. Lack of a season of birth effect among American athletes. _Perceptual and Motor Skills_, _81_(3), pp.952-954.))
The early maturation levels giving physical advantages to first quarter individuals can create the bias ((Delorme, N., Chalabaev, A. and Raspaud, M., 2011. Relative age is associated with sport dropout: evidence from youth categories of French basketball. _Scandinavian journal of medicine & science in sports_, _21_(1), pp.120-128.)) seen in players height in Basketball,((Delorme, N. and Raspaud, M., 2009. The relative age effect in young French basketball players: a study on the whole population. _Scandinavian journal of medicine & science in sports_, _19_(2), pp.235-242.)) dominant hand in Tennis, ((Loffing, F., Schorer, J. and Cobley, S.P., 2010. Relative Age Effects are a developmental problem in tennis: but not necessarily when you’re left‐handed!. _High Ability Studies_, _21_(1), pp.19-25.)) or size in a Cricket position, ((Côté, J., Macdonald, D.J., Baker, J. and Abernethy, B., 2006. When “where” is more important than “when”: Birthplace and birthdate effects on the achievement of sporting expertise. _Journal of sports sciences_, _24_(10), pp.1065-1073.)) but physical size isn’t always the cause. ((Sherar, L.B., Baxter-Jones, A.D., Faulkner, R.A. and Russell, K.W., 2007. Do physical maturity and birth date predict talent in male youth ice hockey players?. _Journal of sports sciences_, _25_(8), pp.879-886.))
Older individuals could also gain more competence ((Harter, S., 1993. Causes and consequences of low self-esteem in children and adolescents. In _Self-esteem_ (pp. 87-116). Springer, Boston, MA.)) and self-efficacy ((Heffernan, C.J., 1988. Social foundations of thought and action: A social cognitive theory, Albert Bandura Englewood Cliffs, New Jersey: Prentice Hall, 1986, xiii+ 617 pp. Hardback. US $39.50. _Behaviour Change_, _5_(1), pp.37-38.)) increasing the performance gap, these advantages leading to increased dropout rates for Q1 births. ((García, M.S., Aguilar, Ó.G., Romero, J.J.F., Lastra, D.F. and Oliveira, G.E., 2014. Relative age effect in lower categories of international basketball. _International review for the sociology of sport_, _49_(5), pp.526-535.)) ((Delorme, N., Boiché, J. and Raspaud, M., 2010. Relative age and dropout in French male soccer. _Journal of sports sciences_, _28_(7), pp.717-722.)) However, for sports where height and mass impede flexibility, rotational speed and the strength to mass ratio, the maturational delay may be preferred as seen in Gymnastics ((Baxter-Jones, A.D., 1995. Growth and development of young athletes. _Sports medicine_, _20_(2), pp.59-64.)) and other early specializing sports.
With an adult group the relative age has the opposite meaning, ((Medic, N., Starkes, J.L. and Young, B.W., 2007. Examining relative age effects on performance achievement and participation rates in Masters athletes. _Journal of Sports Sciences_, _25_(12), pp.1377-1384.)) as performance declines in age, ((Baker, J., Deakin, J., Horton, S. and Pearce, G.W., 2007. Maintenance of skilled performance with age: a descriptive examination of professional golfers. _Journal of Aging and Physical Activity_, _15_(3), pp.300-317.)) the effect is more significant with more physically demanding sports, ((Thelen, D.G., Schultz, A.B., Alexander, N.B. and Ashton-Miller, J.A., 1996. Effects of age on rapid ankle torque development. _The Journals of Gerontology Series A: Biological Sciences and Medical Sciences_, _51_(5), pp.M226-M232.)) and it depends what age the average peak performance level is, in that sport. ((Starkes, J.L., Weir, P.L., Parmjit, S., Hodges, N.J. and Kerr, T., 1999. Aging and the retention of sport expertise. _International Journal of Sport Psychology_, _30_(2), pp.283-301.)) The “underdog effect” ((Gibbs, B.G., Jarvis, J.A. and Dufur, M.J., 2012. The rise of the underdog? The relative age effect reversal among Canadian-born NHL hockey players: A reply to Nolan and Howell. _International Review for the Sociology of Sport_, _47_(5), pp.644-649.)) has shown that those late birth individuals may see better chances ((Schorer, J., Cobley, S., Büsch, D., Bräutigam, H. and Baker, J., 2009. Influences of competition level, gender, player nationality, career stage and playing position on relative age effects. _Scandinavian journal of medicine & science in sports_, _19_(5), pp.720-730.)) if they are selected to play, ((Romann, M. and Fuchslocher, J., 2014. The need to consider relative age effects in women’s talent development process. _Perceptual and motor skills_, _118_(3), pp.651-662.)) with the advantage decreasing after selection. ((Vaeyens, R., Philippaerts, R.M. and Malina, R.M., 2005. The relative age effect in soccer: A match-related perspective. _Journal of sports sciences_, _23_(7), pp.747-756.))
RAE can work for the younger individuals resulting in higher chances of professional success as time goes on, ((Gil, S.M., Bidaurrazaga-Letona, I., Larruskain, J., Esain, I. and Irazusta, J., 2021. The relative age effect in young athletes: A countywide analysis of 9–14-year-old participants in all competitive sports. _PloS one_, _16_(7), p.e0254687.)) playing more ((Steingröver, C., Wattie, N., Baker, J. and Schorer, J., 2016. Does relative age affect career length in North American professional sports?. _Sports medicine-open_, _2_(1), pp.1-7.)) and having better performances, ((Bjerke, Ø., Pedersen, A.V., Aune, T.K. and Lorås, H., 2017. An inverse relative age effect in male alpine skiers at the absolute top level. _Frontiers in psychology_, _8_, p.1210.)) ((Ramos-Filho, L. and Ferreira, M.P., 2021. The reverse relative age effect in professional soccer: an analysis of the Brazilian National League of 2015. _European Sport Management Quarterly_, _21_(1), pp.78-93.)) fewer injuries, ((Wattie, N., Cobley, S., Macpherson, A., Howard, A., Montelpare, W.J. and Baker, J., 2007. Injuries in Canadian youth ice hockey: the influence of relative age. _Pediatrics_, _120_(1), pp.142-148.)) and longer careers ((Gibbs, B.G., Jarvis, J.A. and Dufur, M.J., 2012. The rise of the underdog? The relative age effect reversal among Canadian-born NHL hockey players: A reply to Nolan and Howell. _International Review for the Sociology of Sport_, _47_(5), pp.644-649.)) potentially due to the underdog effect or talent. ((Cumming, S.P., Searle, C., Hemsley, J.K., Haswell, F., Edwards, H., Scott, S., Gross, A., Ryan, D., Lewis, J., White, P. and Cain, A., 2018. Biological maturation, relative age and self-regulation in male professional academy soccer players: a test of the underdog hypothesis. _Psychology of Sport and Exercise_, _39_, pp.147-153.)) ((McCarthy, N., Collins, D. and Court, D., 2016. Start hard, finish better: further evidence for the reversal of the RAE advantage. _Journal of sports sciences_, _34_(15), pp.1461-1465.))
Playing position, federation membership, and individual and team performance also contribute to the effect ((Rubia, A.D.L., Bjørndal, C.T., Sánchez-Molina, J., Yagüe, J.M., Calvo, J.L. and Maroto-Izquierdo, S., 2020. The relationship between the relative age effect and performance among athletes in World Handball Championships. _PloS One_, _15_(3), p.e0230133.)) with older players having a higher risk of injury. ((Wattie, N., Cobley, S., Macpherson, A., Howard, A., Montelpare, W.J. and Baker, J., 2007. Injuries in Canadian youth ice hockey: the influence of relative age. _Pediatrics_, _120_(1), pp.142-148.))
Hancock ((Hancock, D.J., Adler, A.L. and Côté, J., 2013. A proposed theoretical model to explain relative age effects in sport. _European journal of sport science_, _13_(6), pp.630-637.)) illustrated the connections and interactions between all the social agents shown in the image below.
In education
The Academic year is decided by national education authorities with August or September being common cut-off dates in the Northern Hemisphere and February or March cut-off dates in the Southern Hemisphere.
The relative age effect is evident in education ((Fukunaga, H., Taguri, M. and Morita, S., 2013. Relative age effect on Nobel laureates in the UK. _JRSM short reports_, _4_(10), p.2042533313492514.)) ((Jeronimus, B.F., Stavrakakis, N., Veenstra, R. and Oldehinkel, A.J., 2015. Relative age effects in Dutch adolescents: Concurrent and prospective analyses. _PloS one_, _10_(6), p.e0128856.)) with older students on average scoring higher marks, getting into gifted and talented programs, ((Cobley, S., McKenna, J., Baker, J. and Wattie, N., 2009. How pervasive are relative age effects in secondary school education?. _Journal of Educational Psychology_, _101_(2), p.520.)) and are more likely to attend higher education ((Bedard, K. and Dhuey, E., 2006. The persistence of early childhood maturity: International evidence of long-run age effects. _The Quarterly Journal of Economics_, _121_(4), pp.1437-1472.)) in academic schools over vocational schools, ((Ponzo, M. and Scoppa, V., 2014. The long-lasting effects of school entry age: Evidence from Italian students. _Journal of Policy Modeling_, _36_(3), pp.578-599.)) not necessarily due to higher intelligence. ((Shearer, E., 1967. THE EFFECT OF DATE OF BIRTH ON TEACHERS’ASSESSMENTS OF CHILDREN. _Educational Research_, _10_(1), pp.51-56.)) The Matthew effect again plays a role, as the skills learned early in education compound overtime increasing the advantage, ((Cunha, F., Heckman, J.J., Lochner, L. and Masterov, D.V., 2006. Chapter 12 Interpreting the Evidence on Life Cycle Skill Formation. Handbook of the Economics of Education, 1 (06), 697–812.)) with older students becoming more likely to take up leadership roles. ((Dhuey, E. and Lipscomb, S., 2008. What makes a leader? Relative age and high school leadership. _Economics of education Review_, _27_(2), pp.173-183.)) However, like in sport, the effect diminishes over time after middle school, ((Hauck, A.L. and Finch Jr, A.J., 1993. The effect of relative age on achievement in middle school. _Psychology in the Schools_, _30_(1), pp.74-79.)) and those born later in the year performing better in university education. ((Russell, R.J.H. and Startup, M.J., 1986. Month of birth and academic achievement. _Personality and Individual Differences_, _7_(6), pp.839-846.))
In leadership
The relative age effect has also been observed in the context of leadership. An over-representation starts in high-school leadership activities such as sports team captain or club president. ((Dhuey, E. and Lipscomb, S., 2008. What makes a leader? Relative age and high school leadership. _Economics of education Review_, _27_(2), pp.173-183.)) Then in adult life, this over-representation has been observed in top managerial positions (CEOs of S&P 500 companies), ((Du, Q., Gao, H. and Levi, M.D., 2012. The relative-age effect and career success: Evidence from corporate CEOs. _Economics Letters_, _117_(3), pp.660-662.)) and in top political positions, both in the USA (senators and representatives), ((Muller, D. and Page, L., 2016. Born leaders: political selection and the relative age effect in the US Congress. _Journal of the Royal Statistical Society. Series A (Statistics in Society)_, pp.809-829.)) and in Finland(MPs). ((Tukiainen, J., Takalo, T. and Hulkkonen, T., 2017. Gender specific relative age effects in politics and football.))
Reducing the effect
Various methods have been suggested and tested to reduce the relative age effect like moving the cut-off dates, ((Musch, J. and Grondin, S., 2001. Unequal competition as an impediment to personal development: A review of the relative age effect in sport. _Developmental review_, _21_(2), pp.147-167.)) expanding the age group range, ((Boucher, J. and Halliwell, W., 1991. The novem system: A practical solution to age grouping. _CAHPER Journal_, _57_(1), pp.16-20.)) birthdate quotas for the players ((Barnsley, R.H. and Thompson, A.H., 1988. Birthdate and success in minor hockey: The key to the NHL. _Canadian Journal of Behavioural Science/Revue canadienne des sciences du comportement_, _20_(2), p.167.)) the average age in a team, ((Helsen, W.F., Starkes, J.L. and Van Winckel, J., 1998. The influence of relative age on success and dropout in male soccer players. _American Journal of Human Biology: The Official Journal of the Human Biology Association_, _10_(6), pp.791-798.)) or grouping by height and weight. ((Musch, J. and Grondin, S., 2001. Unequal competition as an impediment to personal development: A review of the relative age effect in sport. _Developmental review_, _21_(2), pp.147-167.)) All of these methods have struggled to find success due to the effect moving with selected dates. ((Helsen, W.F., Starkes, J.L. and Van Winckel, J., 2000. Effect of a change in selection year on success in male soccer players. _American Journal of Human Biology: The Official Journal of the Human Biology Association_, _12_(6), pp.729-735.)) However, making the relative age known to the individuals in the environment have shown less bias in talent identification reducing the relative age effect. ((Mann, D.L. and van Ginneken, P.J., 2017. Age-ordered shirt numbering reduces the selection bias associated with the relative age effect. _Journal of sports sciences_, _35_(8), pp.784-790.))
Birthday banding, ((Kelly, A.L., Jackson, D.T., Taylor, J.J., Jeffreys, M.A. and Turnnidge, J., 2020. ” Birthday-banding” as a strategy to moderate the relative age effect: A case study into the England Squash Talent Pathway. _Frontiers in Sports and Active Living_, _2_, p.145.)) and re-calculating scores based on relative age ((Romann, M. and Cobley, S., 2015. Relative age effects in athletic sprinting and corrective adjustments as a solution for their removal. _PLoS One_, _10_(4), p.e0122988.)) are other methods used to reduce the effects with bio-banding ((Reeves, M.J., Enright, K.J., Dowling, J. and Roberts, S.J., 2018. Stakeholders’ understanding and perceptions of bio-banding in junior-elite football training. _Soccer & Society_, _19_(8), pp.1166-1182.)) seeing the most research, showing benefit to early and late maturing players ((Hill, M., Spencer, A., McGee, D., Scott, S., Frame, M. and Cumming, S.P., 2020. The psychology of bio-banding: a Vygotskian perspective. _Annals of Human Biology_, _47_(4), pp.328-335.)) in both academy football and ((Bradley, B., Johnson, D., Hill, M., McGee, D., Kana-Ah, A., Sharpin, C., Sharp, P., Kelly, A., Cumming, S.P. and Malina, R.M., 2019. Bio-banding in academy football: player’s perceptions of a maturity matched tournament. _Annals of human biology_, _46_(5), pp.400-408.)) recreational football. ((Romann, M., Lüdin, D. and Born, D.P., 2020. Bio-banding in junior soccer players: a pilot study. _BMC research notes_, _13_(1), pp.1-5.)) Bio-banding can help promote appropriate training loads and reduce injury risk, ((Malina, R.M., Cumming, S.P., Rogol, A.D., Coelho-e-Silva, M.J., Figueiredo, A.J., Konarski, J.M. and Kozieł, S.M., 2019. Bio-banding in youth sports: background, concept, and application. _Sports Medicine_, _49_(11), pp.1671-1685.)) while increasing technical demands from players ((Abbott, W., Williams, S., Brickley, G. and Smeeton, N.J., 2019. Effects of bio-banding upon physical and technical performance during soccer competition: a preliminary analysis. _Sports_, _7_(8), p.193.)) however, sports are already categorized by maturation metrics like Judo, ((Giudicelli, B.B., Luz, L.G., Sogut, M., Massart, A.G., Júnior, A.C. and Figueiredo, A.J., 2020. Bio-banding in judo: the mediation role of anthropometric variables on the maturation effect. _International journal of environmental research and public health_, _17_(1), p.361.)) may not see those effects. More longitudinal studies are needed ((Stănilă, A.M., Lupşa, M.M. and Stănilă, C., 2020. BIO-BANDING from concept to practice in sports. _Timisoara Physical Education and Rehabilitation Journal_, _13_(24), pp.19-24.)) alongside more reliable ways to band individuals ((Reeves, M.J., Enright, K.J., Dowling, J. and Roberts, S.J., 2018. Stakeholders’ understanding and perceptions of bio-banding in junior-elite football training. _Soccer & Society_, _19_(8), pp.1166-1182.)) as biological, psychological and social development doesn’t progress in synchrony ((Cumming, S.P., Lloyd, R.S., Oliver, J.L., Eisenmann, J.C. and Malina, R.M., 2017. Bio-banding in sport: applications to competition, talent identification, and strength and conditioning of youth athletes. _Strength & Conditioning Journal_, _39_(2), pp.34-47.)) creating varying imbalances in the groups.
Conclusion
The relative age effect is a socially constructed effect that affects youth development and talent identification which requires awareness and actions taken by any individual involved in the development of the youth population.
