Relative Age Effect Research Articles

한국 고교 야구선수의 프로야구 신인 지명 영향 요인 분석 : 의사결정나무분석을 이용하여

Purpose: The purpose of this study is to analyze the variables that affect being picked for Korean professional baseball in high school baseball players. For this, as analysis variables, team’s (long term and short term) awards, individual’s awards, height, weight, metropolitan area, and metropolitan cities were used.<BR> Method: The subjects of the study were 3rd-grade high school baseball players registered with the Korea Baseball Association from 2014 to 2019 (N=4220). The subjects were divided into three groups: Retirement after high school（n=1597, 38%), university entrance (n=2147, 51%) and picked in professional baseball draft (n=476, 11%). To analyze the differences among groups, Kruskal-Wallis H, Tukey’s post-test, and chi-square test were performed. A decision tree analysis was conducted to analyze being picked prediction models in professional baseball draft and for intuitive understanding.<BR> Results: The results of this study are as follows. 1) The team’s long-term award, short-term (2 years) award, and individual award influenced the high school baseball player’s being picked in the professional baseball draft. Among these, the individual’s awards were identified as the most decisive variable. 2) Height and weight were found to have an effect on the being picked, and height was found to be a more decisive variable. 3) The metropolitan area did not affect the being picked, and the metropolitan cities influenced being picked in the professional baseball draft. 4) There was no relative age effect on the being picked in professional baseball draft of high school baseball players.<BR> Conclusion: In summary, this study emphasizes that physical conditions and regional characteristics can influence the being picked in professional baseball draft, in addition to direct performance indexes such as team awards and individual awards.

Efecto de la edad relativa en la élite del balonmano femenino español y su relación con aspectos antropométricos, de rendimiento y velocidad de lanzamiento.

El efecto de la edad relativa es un aspecto de relevancia en el deporte en general y en balonmano en particular. Ha sido objeto de gran cantidad de estudios centrados mayoritariamente en deporte masculino. Los estudios sobre la edad relativa en balonmano femenino, no son tan numerosos, y no aclaran el efecto de la misma en esta modalidad deportiva. Por ello, el objetivo de este estudio fue determinar la existencia del efecto de la edad relativa en jugadoras de élite de balonmano, así como valorar dicho efecto en función de variables antropométricas, de condición física y técnico tácticas (velocidad de lanzamiento). Han sido evaluadas 136 jugadoras de balonmano de los ocho primeros equipos de división de honor. Se ha encontrado un efecto de la edad relativa (con la prueba de chi-cuadrado) en las jugadoras de balonmano, sustentado por aquellas que formaron parte de los equipos nacionales. No se encontraron efectos de la edad relativa en las variables antropométricas, ni en las velocidades de lanzamiento con y sin interacción. La lateralidad y el Squat Jump (SJ), presentaron un efecto de la edad relativa. El efecto de la edad relativa es importante para llegar a la selección, pero para jugar en la máxima categoría el efecto de la edad relativa no es tan importante. Son necesarios más estudios sobre el efecto de la edad relativa en el balonmano femenino. Relative age effect is an aspect of relevance in sport in general and in handball in particular. It has been the subject of a great number of studies focused largely on men's sport. Studies on relative age in female handball are not so numerous, and do not clarify the effect of female handball on this sport. Therefore, the aim of this study was to establish the effect of relative age on élite handball players, as well as to assess this effect based on anthropometric variables, physical fitness and technical and tactical skills (throwing speed). 136 handball players from the first eight honour division teams have been assessed. A relative age effect has been found (with chi-square test) in the handball players supported by those included in national teams. No effects of relative age were found on anthropometric variables, nor on throwing speed with and without interaction. Laterality and Squat Juam (SJ) presented a relative age effect. Relative age is important to reach the national team, but to play in the highest category the effect of relative age seems to lose weight Further studies on the effect of relative age on women's handball are needed. O efeito da idade relativa é um aspecto de relevância no desporto em geral e no andebol em particular. Tem sido objeto de elevado número de estudos centrados em grande parte no andebol masculino. Os estudos sobre a idade relativa no andebol feminino, não são tão numerosos, e não clarejam o efeito da mesma nesta modalidade esportiva. Por isso, o objetivo deste estudo foi determinar a existência do efeito da idade relativa em jogadoras de élite de andebol, assim como valorar este efeito em função das variáveis antropométricas, de condição física e técnico-táticas (velocidade de remate). Foram avaliadas 136 jogadoras de andebol das oito primeiras equipas da divisão de honra. Encontrou-se um efeito de idade relativa (foi usado o teste qui-quadrado) nas jogadoras de andebol sustentado pelas que participam nas seleções nacionais. Não se encontrou efeitos de idade relativa nas variáveis antropométricas, nem na velocidade de remate com e sem interação. A lateralidade e o Squat Juam (SJ) apresentaram um efeito de idade relativa. A idade relativa é importante para chegar às seleções, mas para jogar na categoria máxima o efeito da idade relativa parece perder significado. São necessários mais estudos sobre o efeito da idade relativa no andebol feminino.

The relative age effect is more than just participation bias in badminton

Background: Annual age grouping is a widely used strategy to allocate players to age categories for more equal and fair opportunities considering the developmental differences. Although it is a well-intended strategy, certain (dis)advantages occur because of the subtle age-related differences within the same age groups. Objective: The purpose of the current study was to investigate the relative age effect among badminton players reaching the podium in the last three consecutive European U15, U17 and Junior (U19) Badminton Championships. Methods: A total of 288 medal owners from 20 countries were evaluated in the study. Chi-square (χ2) goodness-of-fit tests were used to compare the obtained birth month distributions across the quartiles (Q), and odds ratios and 95% confidence intervals were calculated in order to compare quartiles with each other. Results: Statistically significant relative age effects were determined favouring relatively older athletes in the total sample (χ2 = 82.278, p < .001). Statistically significant distribution differences were noted in both singles and doubles categories in total (χ2 = 18.778, p < .001; χ2 = 63.815, p < .001, respectively). Striking findings were determined in Q1-Q4 and Q2-Q4 comparisons as players in Q1 and Q2 were more than five and four times as likely to reach the podium than players in Q4, respectively. Conclusions: Results of this study confirm the presence of relative age effect among award-winning badminton players which goes beyond the classical participation trends findings, and stress the importance of the issue for talent development, selection and success.

Reproductive performance in houbara bustard is affected by the combined effects of age, inbreeding and number of generations in captivity

Although captive breeding programs are valuable for conservation, they have been shown to be associated with genetic changes, such as adaptation to captivity or inbreeding. In addition, reproductive performance is strongly age-dependent in most animal species. These mechanisms that potentially impact reproduction have often been studied separately, while their interactions have rarely been addressed. In this study, using a large dataset of nine male and female reproductive parameters measured for 12,295 captive houbara bustards (Chlamydotis undulata undulata) over 24 years, we investigated the relative and interactive effects of age, inbreeding and number of generations in captivity on reproduction. We clearly identified (1) senescence patterns in all parameters studied; (2) negative effects of inbreeding on sperm characteristics, display behavior, egg weight, egg volume and hatching probability; and (3) changes in phenotypic values for seven parameters according to number of generations in captivity. However, the effect sizes associated with age were substantially greater than those associated with inbreeding and number of generations in captivity. Beyond the independent effects of these three factors on reproductive parameters, the results highlighted their interactive effects and thus the importance of integrating them in the design of genetic management plans for conservation breeding programs.

Relative Age Effect on Some Motorical Properties of Young Football Players

Relative Age Effect on Some Motorical Properties of Young Football Players

Handedness and Relative Age in International Elite Interactive Individual Sports Revisited.

Relative age effects (RAE) describe the unintended side effect of annual age grouping such that athletes born close to a specific cutoff date are more likely to be associated with attaining higher performance status than athletes born later. One factor suggested to override the RAE is handedness. Given the left-handers' rarity and their proposed performance advantage in interactive sports, left-handedness may be associated with a lower likelihood of suffering from selection inequalities like RAE in those sports compared with right-handedness. Here, in a two-study approach, we tested that hypothesis by examining male and female athletes from various interactive individual sports sampled over a 10-year period from 2007 to 2016. Study 1 investigated distributions of birth and handedness of senior athletes listed in the top 200 of year-end world rankings in table tennis, tennis, squash, and fencing (épée, foil, and saber). Study 2 followed a similar design but focused on junior athletes in the fencing disciplines and tennis. Unlike the above prediction, in both studies, birth distribution was not found to be reliably associated with handedness in any of the sports or disciplines considered. Left-handers were consistently overrepresented in épée, foil, and table tennis, occasionally in saber and tennis, and not at all in squash. Birth frequencies decreased from quartile Q1 (January to March) to Q4 in almost any sporting domain at the junior level, whereas such trend was rarely found at the senior level. In conclusion, while providing novel insight on the role handedness may play at the junior level, our findings do not support the hypothesis that left-handedness helps override birth-related inequalities in high sporting achievement in elite interactive individual sports.

Confusion Reigns: An Analysis of Responses to U.S. Soccer Age Cut-Off Date Policy Change.

Relative age effects (RAEs) have been associated with the common practice of grouping athletes by chronological age. Development and selection advantages are often awarded to those who are born closer to, but following, the cut-off date employed by sport systems. In 2015, the U.S. Soccer Federation announced that it would be changing its birth-year registration cut-off date from August 1st to January 1st. This change was introduced to align the U.S. youth soccer calendar with international standards, and simultaneously provide clearer information on player birthdates to “lessen” RAEs. The magnitude of this policy change has led to considerable controversy, with members of the soccer community taking to social media and website blogs, as well as the U.S. Youth Soccer's website, to voice their opinions and general unhappiness with this decision. Thus, the purpose of this study was to provide a summary of online reactions to the policy change, with attention to the manner in which the U.S. Soccer Federation framed (i.e., the underlying rationale for the decision) and publicly communicated its decision to change the annual cut-off date. Qualitative content analysis was used to analyze data collected from 63 social media sites (websites, n = 43; forums, n = 16; blogs, n = 4). From the 3,851 pages of text derived from these sources, a total of 404 unique passages of text were identified within 262 stakeholder posts. Four categories emerged from the data: stakeholder discussion, outcomes identified by stakeholders, recommended courses of action, and communication regarding the policy change. In general, the actions of the U.S. Soccer Federation and related outcomes were negatively perceived by stakeholders at various levels of the sport. Resistance to the change may have been reduced through enhanced communication from the national level and opportunities for stakeholder input. While one objective of this policy change was to combat RAEs, previous research suggests this organizational change will only shift which group of athletes experience relative age (dis)advantages. There appears to be a disconnect between the academic literature and sport policy with respect to solutions for RAEs, which can lead to unintended consequences for various sport stakeholders.

Does it pay to be one of the oldest in class? Relative age effects on academic self-concept, peer relations, and teacher judgments in German primary schools

Several studies have revealed that older students in a year group reach higher achievement scores than younger students in that group. But less is known about how students' relative age in class relates to their self-perception of academic achievement, their social acceptance in class and to how teachers judge their abilities. Therefore, we examined relative age effects within class on students' academic self-concept, peer relations, grades, and teachers’ secondary school recommendation. Analyses were based on a sample of N = 18,956 German fourth graders, who had never been retained or accelerated. We applied multilevel regression to control for covariates at the individual and classroom level. There were no substantial relative age effects within class across any of the outcomes, except for a small advantage for the youngest in their reading self-concept. Our findings therefore contradict the common assumption that younger students in class are disadvantaged compared to their older classmates.

Relative Age Effect in 14- to 18-Year-Old Athletes and Their Initial Approach to This Effect-Has Anything Changed Over the Past 10 Years?

One of the environmental variables associated with early talent development and the achievement of a high level of proficiency in sport is the relative age effect (RAE). The purpose of our study was threefold: (a) to calculate the RAE in young Israeli athletes (ages 14–18 years); (b) to examine how the athletes perceived this effect, if the effect indeed exists; and (c) to compare the RAE findings of this study with those of two previous studies on elite male (Lidor et al., 2010) and female (Lidor et al., 2014) Israeli ballplayers. Participants in the current study were 1,397 athletes (390 females and 1,007 males) who competed in five individual (gymnastics, judo, swimming, tennis, and track and field) and five team (basketball, soccer, team handball, volleyball, and water polo) sports. Data on the RAE, as well as on a number of aspects associated with this effect as perceived by the athletes, were collected via two closed questions. Data analyses showed that the RAE was found to be significant among the male athletes in four sports—swimming, basketball, soccer, and team handball; those who were born early in the year had a higher representation in these sport programs. However, this effect was not found to be significant in the female athletes. Most of the female and male athletes did not think that their birth date influenced their athletic success. However, a large portion of those who were born in the first quarter of the year (Q1) and the second quarter of the year (Q2) among the male athletes felt that they exhibited stronger abilities in the sports program compared to their peers who were born in the third and fourth quarters of the year (Q3 and Q4, respectively). The data of the current study provide additional support for the use of an “open door” approach to accepting children to sport programs by policymakers and coaches in Israel.

The Influence of Contextual Aspects in Talent Development: Interaction Between Relative Age and Birthplace Effects in NBA-Drafted Players.

The aims of this study were two-fold: (1) to inspect separately for the relative age and birthplace effects for players selected in the National Basketball Association (NBA) draft; (2) to explore the interaction among these factors and analyse this interaction in players' career performance. The database was obtained from the official records of the players (n = 1,738), who were selected during the annual editions of the NBA Draft from 1990 to 2019. The participants' date of birth was analyzed according to the month of birth and divided into four quartiles. The place of birth was compared to the distribution of the general population' places of birth based on different communities' sizes. Chi-square analysis were used to determine if the relative age and birthplace of the players drafted differed in any systematic way from official census population distributions. Cluster analysis and standardized residuals were calculated to analyse the interaction among the contextual factors and the players' career performance. The data revealed that early-born players (Q1 and Q2) were over-represented. Moreover, players born in smaller cities (<100,000) were over-represented. The interaction analysis revealed that the players born in the bigger communities relate mainly with relatively younger players, and clusters that correspond to players born in smaller communities integrated the relatively older players. No differences were found in the players' career performance. Researchers, coaches and practitioners should be aware of the interaction between contextual factors to help nurture the development of sport talent regardless of age-related issues or communities' size.

Gender Differences on Motor Competence in 5-Year-Old Preschool Children Regarding Relative Age.

The aim of this study was to evaluate the differences on motor competence between 5-year-old boys and girls and to investigate the existence of Relative Age Effect (RAE) on their motor competence. A total of 232 preschool children were evaluated of whom 134 (57.8%) were boys and 98 (42.2%) were girls. The Movement Assessment Battery for Children-2 (MABC-2) was used to collect data. The data show a main effect on gender factor; there was a main effect in total score of manual dexterity (MD; p = 0.010), in total score of balance (Bal; p < 0.001), in total test score (TTS; p < 0.001), and in total percentile score (TPS, p < 0.001). In the semester of birth factor, there were differences in aiming and catching (A&C, p < 0.001), in Bal (p = 0.029) and in total percentile score (TPS, p = 0.010). Girls perform better in MD, Bal, TTS, and TPS than boys. Preschool children born in the first semester obtain, in general, a higher percentage and a higher percentile than their peers born in the second one. RAE is present in A&C, Bal, and TPS, with higher scores obtained by preschool children born in the first semester compared to those born in the second one.

Excess mortality for men and women above age 70 according to level of care during the first wave of COVID-19 pandemic in Sweden: A population-based study.

BackgroundBoth age and comorbidity are established risk factors for death among those infected with COVID-19. Because they often co-exist, it is difficult to assess if age is a risk factor on its own.MethodsWe used administrative register data of the total Swedish population from 01/2015 until 07/2020. We stratified the population aged 70+ into three groups according to level of care (in care homes, with home care, and in independent living). Within these groups, we explored the level of excess mortality in 2020 by estimating expected mortality with Poisson regression and compared it to observed levels. We investigated if excess mortality has been of the same magnitude in the three groups, and if age constitutes a risk factor for death during the pandemic regardless of level of care.FindingsIndividuals living in care homes experienced the highest excess mortality (75- >100% in April, 25–50% in May, 0–25% in June, depending on age). Individuals with home care showed the second highest magnitude (30–60% in April, 15–40% in May, 0–25% in June), while individuals in independent living experienced excess primarily at the highest ages (5–50% in April, 5–50% in May, 0–25% in June). Although mortality rates increased, the age-pattern of mortality during the pandemic resembled the age-pattern observed in previous years.InterpretationWe found stepwise elevated excess mortality by level of care during the first wave of the COVID-19 pandemic in Sweden, suggesting that level of frailty or comorbidities plays a more important role than age for COVID-19 associated deaths. Part of our findings are likely attributable to differences in exposure to the virus between individuals receiving formal care and those living independently, and not only different case fatality between the groups. Although age is a strong predictor for mortality, the relative effect of age on mortality was no different during the pandemic than before. We believe this is an important contribution to the discussion of the pandemic, its consequences, and which groups need the most protection.FundingThis study was funded by the Swedish Research Council for Health, Working Life and Welfare (FORTE: grant 2016-07115).

Relative age and specific learning disorder diagnoses: AFinnish population-based cohort study.

Being among the youngest in class has previously been associated with attention-deficit/hyperactivity disorder (ADHD) and academic disadvantage, but the relative age effect on learning disorders is less well understood. This study examined whether relatively young children are more likely to be diagnosed with specific learning disorders than their older peers. The setting included all 388,650 children born singleton in Finland from 1996 to 2002. Cases diagnosed with specific learning disorders in specialized health care by the age of 10 were identified from national registers. Cumulative incidences of specific learning disorders and the corresponding incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated for each birth month compared to January. During follow-up, 3162 (0.8% of 388,650) children were diagnosed with a specific learning disorder. Children born in December displayed higher cumulative incidences for specific learning disorders than children born in January (IRR: 1.77, 95% CI: 1.50-2.11). The findings were similar for girls (IRR: 2.01, 1.44-2.83) and boys (IRR: 1.70, 1.39-2.08). ADHD did not explain the association, as the IRR for the youngest children with specific learning disorders and ADHD was 1.59 (1.13-2.26) compared to those without ADHD (IRR: 1.84, 1.51-2.24). Relatively younger children in Finnish schools were more likely to be diagnosed with a specific learning disorder by the age of 10. Increased awareness of how relative age differences affect the likelihood for children to be diagnosed with specific learning disorders is needed among parents, clinicians, and teachers.

From Talent Identification to Novo Basquete Brasil (NBB): Multifactorial Analysis of the Career Progression in Youth Brazilian Elite Basketball.

This study examined individual, task, and environmental constraints that influence the career progression of youth Brazilian elite basketball players and the probability of reaching Novo Basquete Brasil (NBB) and to determine if the association of the relative age effect (RAE) is a key factor in the career progression. The sample consisted of 4,692 male players who were registered to participate in at least one U15, U17, or U22 youth Brazilian basketball championship between 2004 and 2018. Athletes who reached a high-performance level were coded like NBB players (9.6%). The birthdates, height, body mass, playing position, geographic region, club, competition category, and team performance were retrieved from the official data archive of the Brazilian Basketball Confederation and the National Basketball League. The maturity status was estimated using the predicted age at peak height velocity. A binary logistic regression examined the influence of each characteristic on the probability of a youth Brazilian basketball player to reach the NBB. The receiver operating characteristic (ROC) curves and the associated area under the curve (AUC) were used to assess the discriminant ability of the model. The taller and younger players not selected early into national teams, without specialization by playing position, who participated in U22 national championship, migrated to the southeast region, and remained in the formation process over time have a greater chance to reach the NBB. The ROC curve demonstrated an AUC of 93%. A combination of individual, task, and environmental characteristics influences the sport career of a young Brazilian basketball player in reaching the NBB. Further, early-maturing athletes have a greater chance to reach higher performances. RAE influences lower-level categories, but not a “NBB player's” career progression. The coaches, stakeholders, and practitioners should perform a holistic evaluation of sport talent in terms of a constraint-based theoretical model with the aim of avoiding bias produced by the maturational status and RAE in the youth Brazilian elite basketball.

Leveling the Playing Field: A New Proposed Method to Address Relative Age- and Maturity-Related Bias in Soccer.

Despite various solutions proposed to solve the relative age effect (RAE), it is still a major problem confounding talent identification and selection processes. In the first phase, we sampled 302 under 7–21 academy soccer players from two Belgian professional soccer clubs to explore the potential of a new approach to solve the inequalities resulting from relative age- and maturity-related bias. This approach allocates players into four discrete quartile groups based on the midway point of their chronological and estimated developmental (ED) birth dates (calculated using the growth curves for stature of Belgian youth). With the use of chi square analyses, a RAE was found (p < 0.01) for the overall sample (Q1 = 41.4% vs. Q4 = 14.9%) that completely disappeared after reallocation (Q1 = 26.5%; Q2 = 21.9%; Q3 = 27.5%; Q4 = 24.2%). According to the new allocation method, the stature difference was reduced, on average, by 11.6 cm (from 24.0 ± 9.9 to 12.4 ± 3.4 cm, d = 1.57). Body mass difference between the two methods was 1.9 kg (20.1 ± 11.3–18.2 ± 13.1 kg, respectively, d = 0.15). The new method created a maximum chronological age difference of 1.9 vs. 0.8 years for the current method. With the use of this method, 47% of the players would be reallocated. Twenty-three percent would be moved up one age category, and 21% would be moved down. In the second phase, we also examined 80 UK academy soccer players to explore if reallocating players reduces the within-playing group variation of somatic and physical fitness characteristics. The percentage coefficient of variation (%CV) was reduced (0.2–10.1%) in 15 out of 20 metrics across U11–U16 age categories, with the U13 age category demonstrating the largest reductions (0.9–10.1%) in CV. The U12 and U13 age categories and associated reallocation groupings showed trivial to small (ES = 0.0–0.5) between-method differences and trivial to moderate (ES = 0.0–1.1) differences within the U14–U16 age categories. A reduction in RAE may lead to fewer dropouts and thus a larger player pool, which benefits, in turn, talent identification, selection, and development.

Relative Age Effect in Canadian Hockey: Prevalence, Perceived Competence and Performance.

The term “relative age effect” (RAE) is used to describe a bias in which participation in sports (and other fields) is higher among people who were born at the beginning of the relevant selection period than would be expected from the distribution of births. In sports, RAEs may affect the psychological experience of players as well as their performance. This article presents 2 studies. Study 1 aims to verify the prevalence of RAEs in minor hockey and test its associations with players' physical self-concept and attitudes toward physical activities in general. Study 2 verifies the prevalence of the RAE and analyzes the performance of Canadian junior elite players as a function of their birth quartile. In study 1, the sample is drawn from 404 minor hockey players who have evolved from a recreational to an elite level. Physical self-concept and attitudes toward different kinds of physical activities were assessed via questionnaires. Results showed that the RAE is prevalent in minor hockey at all competition levels. Minor differences in favor of Q1-born players were observed regarding physical self-concept, but not attitudes. In study 2, data analyses were conducted from the 2018–2019 Canadian Hockey League database. Birth quartiles were compared on different components of performance by using quantile regression on each variable. Results revealed that RAEs are prevalent in the CHL, with Q1 players tending to outperform Q4 players in games played and power-play points. No other significant differences were observed regarding anthropometric measures and other performance outcomes. RAEs are still prevalent in Canadian hockey. Building up perceived competence and providing game-time exposure are examples of aspects that need to be addressed when trying to minimize RAEs in ice hockey.

Relative age effect on the market value of elite European football players: a balanced sample approach

ABSTRACT Research question Athletes born late in the selection year are disadvantaged compared to the relatively older in youth age groups. This leads to an overrepresentation of the early-born in professional teams, which is called the relative age effect (RAE). Previous studies examine the RAE on wage or market value with contradictory results. This paper aims to estimate the partial RAE on the market value of top-level European football players with a new methodology. Research methods We analysed a data set of players from the biggest five European football leagues over ten seasons (2008-2017). We argue that the conventional estimation of RAE fails to yield a partial effect, due to a sample selection bias. For various regression models, we use a stratified sampling method to balance the birth date distribution and eliminate the bias. Results and Findings Unlike prior studies, we found an extremely strong straight RAE in elite European football, especially for younger players. Using our methodology, we interpret RAE as a partial effect, which indicates that an earlier birth date within the calendar year results in a higher market value. Implications This paper contributes to the literature by proposing a new methodology to measure the partial RAE on labour market outcomes. Our results imply discrimination based on birth date in several countries, which needs to be reduced by better regulation of youth competitions. Our findings have implications for coaches and managers on how to account for relative age when training, transferring, and selecting players.

Darwinian Selection Discriminates Young Athletes: the Relative Age Effect in Relation to Sporting Performance

BackgroundThe relative age effect (RAE) is a worldwide phenomenon, allowing sport participation and elite selection to be based on birthdate distribution. Negative consequences include both a narrow, non-optimal elite selection and negative health effects on entire populations. This study investigated the RAE and athletic performance in multiple individual sports in Sweden.MethodsBirthdates of athletes born between the years 1922 and 2015 were collected across 4-month periods (tertiles: T1, T2, T3) from cross-country skiing (N = 136,387), orienteering (N = 41,164), athletics (N = 14,503), alpine skiing (N = 508), E-sports (N = 47,030), and chess (N = 4889). In total, data from 244,560 athletes (women: N = 79,807, men: N = 164,753) was compared to the complete parent population of 5,390,954 births in Sweden during the same years. Chi-squared statistics compared parent and cohort distributions stratified by sport, sex, and age.ResultsA significantly skewed distribution of birthdates was present in all sports, both sexes, and most age groups. The largest RAEs are seen in children where T1 often constitutes 40–50% and T3, 20–25% of the population. In E-sports, an inversed RAE was seen in adults. In most investigated sports, birthdate distribution was correlated to performance in children but not in adults.ConclusionsSkewed birthdate distributions were consistently prevalent in all investigated individual sports in Sweden, both physically demanding and cognitive/skill-based. As sport participation is related to total level of physical activity, both present and future, failing to address the RAE issue at an early age will result not only in a narrow and arbitrary selection for adult elite athletes but also in a negative impact on public health.

Elite Junior Throwers Unlikely to Remain at the Top Level in the Senior Category.

This study investigated (1)the transition rate of elite world-class throwers, (2)the age of peak performance in either elite junior and/or elite senior athletes, and (3)if relative age effect (RAE) influences the chance of being considered elite in junior and/or senior category. The career performance trajectories of 5108 throwers (49.9% females) were extracted from the World Athletics database. The authors identified throwers who had reached the elite level (operationally defined as the World all-time top 50 ranked for each age category) in either junior and/or senior category and calculated the junior-to-senior transition rate. The age of peak performance and the RAE were also investigated. The transition rate at 16 and 18 years of age was 6% and 12% in males and 16% and 24% in females, respectively. Furthermore, elite senior throwers reached their personal best later in life than elite junior throwers. The athletes of both genders considered elite in the junior category showed a large RAE. Interestingly, male athletes who reached the elite level in senior category also showed appreciable RAE. Only a few of the athletes who reach the top 50 in the world at 16 or 18 years of age manage to become elite senior athletes, underlining that success at the beginning of an athletic career does not predict success in the athlete's senior career. Moreover, data suggest that being relatively older may confer a benefit across the whole career of male throwers.

Born leaders: China’s municipal party secretaries

ABSTRACT Applying relative-age effect theory to China, we examine the political career development of municipal party secretaries. Our analysis presented in this paper provides substantial evidence in favour of those who were older in their cohort at school, i.e., those who were born in October and November are more likely than those who were born in June or July to be advanced to a party leadership position in an earlier time. This research fills in a gap in the field of RAE from a comparative perspective, and it also provides insights into long-term effects of relative age in China’s increasingly competitive political careers that challenge the conventional wisdom in political science literature.