not reach a sufficient level even among the mostcompetitive women’s sports to produce RAE.Also, the earlier maturation of girls and the lowervariability of the maturity status in girls in com-parison to boys[8] can both explain the insignif-icant results. Moreover, in the GuldBagerenLigaen, professional players were more likely tobe born in the last quartile. This finding stands incontrast to the RAE. In order to understand theroots of this effect, a longitudinal research designshould be conducted. One possible account is re-siliency: while for those young athletes who arenot as physically strong in the beginning but re-main in the sport are more likely to persist, therest, once they lose their physical advantage,wither away gradually. This finding is alignedwith the general trend of reduction in magnitudeof RAE with age progression.[1] Future researchshould focus on longitudinal designs that wouldallow separating those variables, shedding morelight on the differences between the sexes.What are the practical implications of the re-

sults? Past research[2] has advocated elaboratesolutions to counter the RAE, such as determin-ing groups based on biological age or variation ofcutoff dates within the competition year. Basedon the current results, sports organizations thatnurture female athletes into taking their firststeps in sports, and who focus primarily on pro-ducing top calibre performers, should not beconcerned with the adverse impact of RAE.

Nadav GoldschmiedUniversity of San Diego, San Diego, California, USA

Acknowledgements

No funding was used to assist in the preparation of thisletter. The author has no conflicts of interest that are directlyrelevant to the content of this letter.

References1. Cobley S, Baker J, Wattie N, et al. Annual age-grouping and

athlete development. Sports Med 2009; 39 (3): 235-56

2. Musch J, Grondin S. Unequal competition as an impedimentto personal development: a review of the relative age effect insport. Dev Rev 2001; 21 (2): 147-67

3. Barnsley RH, Thompson AH. Birthdate and success in minorhockey: the key to the NHL. Can J Behav Sci 1988; 20: 167-76

4. Dudink A. Birth date and sporting success [abstract]. Nature1994; 368: 592

5. Dyer S, Raphaeli M, Goldschmied N. No evidence for therelative age effect in professional women sports [abstract no.1225]. 118th American Psychological Association AnnualMeeting; 2010 Aug 12; San Diego (CA)

6. Edgar S, O’Donoghue P. Season of birth distribution of elitetennis players. J Sport Sci 2005; 23 (10): 1013-20

7. Wattie N, Baker J, Cobley S, et al. A historical examination ofrelative age effects in Canadian hockey players. Int J SportPsychol 2007; 38: 178-86

8. Baxter-Jones A, Helms P, Maffuli N, et al. Growth and de-velopment of male gymnasts, swimmers, soccer and tennisplayers: a longitudinal study. Ann Hum Biol 1995; 22 (5):381-94

Authors’ Reply

Relative Age Effects in FemaleContexts

We thank Dr Goldschmied[1] for his letter tothe editor and welcome his findings, which con-tribute to our understanding of Relative Age Ef-fects (RAEs). Dr Goldschmied’s data do seemto differ from hypothetical expectations (i.e. rela-tively older participants being overrepresented[2]),offering new insight into what now seems an in-creasingly complex effect. When compared withexisting knowledge of male and female samplesin other team sport contexts (e.g. adult femaleCanadian ice hockey,[3] junior representativebasketball[4]), Dr Goldschmied’s observationsoffer contrasts by showing (i) no RAEs in bas-ketball and soccer; and (ii) the relatively youngerparticipants being overrepresented in handball.Whilst understanding that limited detail can

be placed within a letter, prior to further discus-sion it would be prudent to check a few points onGoldschmied’s methods and data analysis. Weassume that a common cut-off date (i.e. September)was applied throughout the relevant stages ofsport participation and development, which isimportant because this is typically where RAEsoriginate. There is a suggestion that a differentcut-off was applied (i.e. August) in the parallelanalysis conducted with ‘local players’. It would

88 Letter to the Editor

ª 2011 Adis Data Information BV. All rights reserved. Sports Med 2011; 41 (1)

be useful to know more about what this extendedanalysis included, but more importantly here, tounderstand why an alternative cut-off date wasused as it differs to that applied for the othersamples. It would also be worth considering whe-ther or not any such cut-off dates have changedover the past 10–20 years (e.g. handball). Suchchanges could have influenced the current adult-elite relative age player profiles. As described inprevious research,[5,6] changed cut-off datesmodifysubsequent participation and attainment profiles.These checks will all help to discount alternativeexplanations for why the relatively younger wereoverrepresented in the context of elite handballand, at the same time, generate further confidencein the reported findings.‘Why?’ is the fundamental question all RAE

researchers ask when they encounter a dispro-portionate representation, or the occurrence ofan enduring inequality based on being relativelyolder.[7] Similarly, we ask this in relation to theabsence of RAEs in female US basketball andsoccer, as well as the overrepresentation of rela-tively younger players in Danish handball (bothof which may be contrary to expectations). Help-fully, Goldschmied offers plausible explanations.A reduced depth of competition, which wouldsupport universal enrolment, could account forthe non-existence of RAEs in female basketballand soccer. Here, the logic is that involvementrarely reflects strict selection for few places. Thereis some evidence to support this notion. For ex-ample, historically RAEs were not apparent inelite women’s ice hockey.[3] However, this situa-tionmay be changing andmore recent observationsof an increasingly popular, more competitive gameand league structure[8] suggest RAEs could haveevolved in parallel with these developments. At thecore of the depth of competition hypothesis ap-pears be the issue of access. If provision (such aslocal school and community clubs) exceeds demandfor participation, there is less of a need for someform of selection (a process that generates RAEs).RAEs may surface when participation demandexceeds local provision capacities.Dr Goldschmied suggests that the absence of

RAEs in basketball and soccer could also be at-tributed to the earlier maturation of girls, along

with a lowered variability of maturity status dur-ing adolescence. Indeed, there are more markeddifferences in physical performance among ado-lescent boys according to early onset or late ma-turation.[9] For girls, this relationship appearsless consistent and/or influential on particularperformance measurements.[10] This highlightsthe potential for performance indicators to be lessconfounded by variable maturation, and for se-lection to be less biased by the markers of differ-ential development. Where a sport, or sportingcontext, values qualities other than physicaldominance, RAEs may be less prevalent or eventotally absent.Psychological resilience is offered as an ex-

planation for the overrepresentation of the rela-tively younger players in Danish handball. Thiscertainly has intuitive appeal if the context ofDanish handball is similar to other sport devel-opment systems (e.g. those seen in Germany).[11]

Here, the mechanism seems to be that relativelyyounger players, even though they are more likelyto be later maturing, maintain participation anddevelopment despite regular exposure to devel-opmentally related disadvantages. As a result,these individuals may acquire/develop a set ofpsychological and/or performance skills that helpthem to circumvent the RAE maturation-selectionproblem, and that eventually may overcome thosewho were initially selected for maturational differ-ences. The withdrawal of those superseded athletes,combined with refined robust psychological copingprofiles of the adherers, may ultimately provide theadherers with delayed advantages in selection,[12]

performance and career longevity.[11]

While each of these mechanisms is plausible,others should still be considered. Importantly,this kind of conjecture highlights the limitationsof cross-sectional studies of the RAE phenomen-on. As we have argued elsewhere,[13] RAE studiesneed to move beyond atheoretical descriptionsin different contexts. We now need hypothesis-driven research that can help to develop a com-prehensive model of RAEs in sport. Where RAEsare present, regardless of sex, there is a need to notonly understand the underpinning mechanisms,but also trial and evaluate intervention studies aimedat resolving their presence. Just as we anticipate

Letter to the Editor 89

ª 2011 Adis Data Information BV. All rights reserved. Sports Med 2011; 41 (1)

that RAEs are context specific, we expect this ofthe interventions too, although this remains to beconfirmed. Thus, the underpinning implementa-tion science will help the RAE field to positivelyinfluence youth participation and elite perfor-mance development.To conclude, we would like to briefly discuss the

implications and generalizability of the presentfindings. DrGoldschmied suggests that the absenceof adverse RAEs, at least for the female sport con-texts examined and their respective governingbodies, means that they should not be of directconcern. However, when referring to the handballdata, we should consider why a disproportionaterepresentation in adulthood ismore acceptablewhenit is based, possibly, on a psychological mechanism,as opposed to a maturation-selection mechanism.That said, we also urge caution in transferringpresent findings to other female sport settings,particularly when such data are not available forassessment. We should keep in mind that RAEsare prevalent in certain female sport contexts,and many further contexts have yet to be exam-ined. With possible increases in female partici-pation rates and evolving talent developmentsystems, RAEs could feature in the future. Suchpossibilities re-emphasize the value and necessityof applied research with local community set-tings, sport governing bodies and their sport de-velopment systems.

Stephen Cobley,1 Nick Wattie,1 Joseph Baker2 andJim McKenna1

1 Carnegie Research Institute, Leeds MetropolitanUniversity, Leeds, West Yorkshire, UK

2 School of Kinesiology and Health Science, YorkUniversity, Toronto, Ontario, Canada

Acknowledgements

No funding was used to assist in the preparation of thisletter. The authors have no conflicts of interest that are di-rectly relevant to the content of this letter.

References1. Goldschmied N. No evidence for the relative age effect in

professional women sports [letter]. Sports Med 41 (1): 87-8

2. Cobley S, Baker J, Wattie N, et al. Annual age-grouping andathlete development. Sports Med 2009; 39 (3): 235-56

3. Wattie N, Baker J, Cobley S, et al. A historical examinationof relative age effects in Canadian hockey players. Int JSport Psychol 2007; 38: 178-86

4. Hoare D. Birthdate and basketball success: is there a relativeage effect? Proceedings of the Pre-Olympic Congress: SportsMedicine and Physical Education International Congress onSports Science; 2000 Sep 7-13; Brisbane (QLD)

5. Musch J,HayR.The relative age effect in soccer: cross-culturalevidence for a systematic discrimination against children bornlate in the competition year. Sociol Sport J 1999; 16: 54-64

6. HelsenWF, Starkes JL, VanWinckel J. Effect of a change inselection year on success in male soccer players. Am J HumBiol 2000; 12: 729-35

7. Till K, Cobley S, Wattie N, et al. The prevalence, influentialfactors and mechanisms of relative age effects in UKRugby League. Scand J Med Sci Sports 2010; 20 (2): 320-9

8. Weir PL, Smith KL, Paterson C, et al. Canadian women’sice hockey: evidence of a relative age effect. Tal Dev Excel2010; 2 (2): 209-17

9. Sherar LB, Baxter-Jones ADG, Faulkner RA, et al. Doesphysical maturity and birth date predict talent in maleyouth ice hockey players? J Sports Sci 2007; 25 (8): 879-86

10. Malina RM, Bouchard C, Bar-Or O. Growth, maturationand physical activity. 2nd ed. Champaign (IL): HumanKinetics, 2004

11. Schorer J, Cobley S, Busch D, et al. Influences of competi-tion level, gender, player nationality, career stage andplaying position on relative age effects. Scand J Med SciSports 2009; 19 (5): 720-30

12. Baker J, Logan AJ. Developmental contexts and sportingsuccess: birth date and birthplace effects in national hockeyleague draftees 2000-2005. Br J Sports Med 2007; 41: 515-7

13. Wattie N, Cobley S, Baker J. Towards a unified understandingof relative age effects. J Sports Sci 2008; 26 (13): 1403-9

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