| Relative Age Studies | |||||||||
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| Month of Birth and Elite Hockey | ||||||||||||||||||||||||||||||
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The Figure at left shows the distribution of birth-months of
players in two Canadian major junior hockey leagues (the Ontario Junior Hockey
League and the Western Hockey League). The data indicate that the probability
of success in high calibre hockey is dramatically reduced for those born at the
end of the year. Furthermore, among National League Hockey Players who were
active in the early 1980s, about 40% were born in the first quarter of the
year, 30% in the second, 20% in the third, and less than 10% were born in the
final quarter. In terms of playing at a high level, boys born in the last part of the year have a much lower chance than those born at the beginning of the year. The fact that January and December, which are juxtaposed, show such dissimilar results, suggests that it is not the weather during conception or birth that has made the difference. |
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| Source: Barnsley RH, Thompson AH, Barnsley PE (1985). Hockey success and birth-date: The relative age effect. Journal of the Canadian Association for Health, Physical Education, and Recreation, Nov.-Dec., 23-28. | ||||||||||||||||||||||||||||||
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| Relative Age and Ranking in Minor Hockey | ||||||||||||||||||||||||||||||
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Minor hockey organizations often divide age groupings up into
"sub-leagues" (tiers) on the basis of skill. If relative age has an effect,
then children who are older when they first play organized hockey would be more
likely to make top tier teams, while the younger players should gravitate to
the bottom tier. The distribution of birthdates of about 8,000 Edmonton
minor-league hockey players (9-15 yrs.) is shown on the left. As predicted, top
tier players did show a strong relative age effect, and bottom tier players
showed a reverse relative age effect. An important finding was that those born in the latter part of the year were more likely to "drop out" of hockey altogether. The data provide support for relative age theory, & suggest that ongoing relative age disadvantage may demoralize some children and cause them to withdraw from competitive activity. |
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| Source: Barnsley RH, Thompson AH (1988). Birthdate and success in minor hockey: The key to the N.H.L. Canadian Journal of Behavioral Science 20, 167-176. Click here for a copy (500 kb) | ||||||||||||||||||||||||||||||
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| Relative Age and Baseball | ||||||||||||||||||||||||||||||
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The upper graph on the left shows the
influence of the relative age effect among Major League Baseball players.
However, the magnitude of the effect is much lower than that found among other
sports like soccer and hockey (see the soccer results for
a graph depicted on the same scale). In an attempt to understand this, we studied Little League players where the effect was presumed to be rooted. Our analysis of team rosters did not reflect the presence of an effect of any significance. It was only when we compared those selected for post-season play with those who were not selected, did an effect emerge. But as the lower figure shows, the differing trends for these two groups showed neither the magnitude nor the clarity found in other sports . This weak effect among professional baseball players was thus hypothesized to be a natural consequence of its weak development during the formative years of Little League. This, in turn, might be explained by the size of the age-range used by Little League teams - often 4 to 5 years - much larger than that found in other team sports. Thus, all budding baseball players are at a disadvantage when they begin, and all will have an advantage in later years. This may neutralize some of the mechanisms that might be "in play" in other sports. Sources: 1. Thompson AH, Barnsley RH, Stebelsky G (1991). Born to play ball: The relative age effect and Major League Baseball. Sociology of Sport Journal, 8, 146-151 (for a copy click here) 2. Thompson AH, Barnsley RH, Stebelsky G (1992). Baseball performance and the relative age effect: Does Little League neutralize birth date selection bias? Nine, 1(1), 19-30. |
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Relative Age and World Class Soccer |
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At the time of data collection for this study, the cutoff
date for entry into organized childrens soccer was August 1st. Thus, those
beginning footballers who were born in August would have been close to a year
older than those in their age-group who were born the following July. As the
accompanying figure shows, the relative age effect had done its work while
these boys were still teen-agers. Those who were able to play at the World
level have been chosen in large part by an accident of birth - whether it be
for the under age 20 tournament or for the under 17s . Nearly half were born in
the first three months of the football eligibility year, while less than seven
percent were born in the final quarter! A relative age effect was also found
for the players involved in the World Cup of Football in 1990, but it was not
as strong. This result is similar to that found for hockey (with perhaps an even stronger effect!). The fact that the cutoff here was August, in contrast to January for hockey, suggests that seasonal/climatic influences associated with the time of birth or gestation are irrelevant to the effect. |
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| Source: Barnsley RH, Thompson AH, Legault P (1992). Family planning: Football style, the relative age effect in football. International Review for the Sociology of Sport 27(1), 77-88. Click here for a downloadable copy (470KB; requires Adobe Reader). | ||||||||||||||||||||||||||||||
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| Relative Age and Academic Achievement | ||||||||||||||||||||||||||||||
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A large body of research has shown that children who enter grade one at a relatively young age do less well than those who are older even though the span from youngest to oldest may be only one year. Children who are younger than their classmates tend to achieve less well, be classed as learning disabled, and show adjustment difficulties. The following Figure shows recent data of this kind for Alberta schoolchildren, with those in the correct age-for-grade falling between the vertical lines. | |||||||||||||||||||||||||||||
| Source: Data provided by Edmonton Public Schools. | ||||||||||||||||||||||||||||||
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| Relative Age and Self-Esteem | ||||||||||||||||||||||||||||||
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Self-esteem may operate between relative age effects and later suicidal behaviour. The relationship between self-esteem as measured by the Culture Free Self-Esteem Inventory (Battle, 1981) and age at entering grade one is shown in the accompanying figure. Note that self-esteem shows a general rise with age for those within the correct age-for-grade range (ages 5-6, to 6-5). The highest self-esteem, however, was reported by the group made up in large part by children who were destined to be youngest in the class, but whose parents apparently delayed school entry by one year, causing them to be among the oldest (i.e. ages 6-6 to 6-8). Those that came from broken homes showed the same pattern, but at a uniformly lower level. | |||||||||||||||||||||||||||||
| Source: Thompson AH, Barnsley RH, Battle J.
(2004). The relative age effect and the development of self-esteem.
Educational Research 46, 313-320. |
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| Relative Age and
Suicide |
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| A theoretical explanation for relative age includes the
belief that its effects are due, in the end, to negative self-appraisal and
diminished self-confidence. These are related to depression and hopelessness,
respectively, thought by many to be the essential components of completed
suicide. Relative age effects among young children, then, might well be
expected to be associated with suicide later in life. The accompanying Table shows the distribution of youth suicides in Alberta from 1979-92 according to age at entering grade one (data are presented separately for each grade one entry cutoff date used in the various school districts). The group of children who were younger entering grade one showed the higher rates in each case. These data indicate that bestowing advantage/disadvantage in a competitive task, albeit inadvertently, can affect emotional development and suicidal behaviour. |
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| Source: Thompson AH, Barnsley RH, Dyck RJ (1999). A new factor in youth suicide: The relative age effect. Canadian Journal of Psychiatry 44(1), 82-85. Click here for the full text. | ||||||||||||||||||||||||||||||
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Background on Relative Age |
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| Paula Barnsley, while attending a Lethbridge
Broncos junior hockey game in the early 1980s, apparently lost interest in the
spectacle in front of her and began to read the game program. Paula noticed
that most of the players were born in months that fell at the beginning of the
calendar year. This began a twenty-year (so far) collaboration on relative age
between Paula's husband, Roger (now President of the University College of the
Cariboo), and myself. Paula, shortly after her discovery, gave up her career as
an educational psychologist, and went into law - a puzzling decision. At about
the same time, Simon Grondin, a graduate student in Psychology at Laval
University, made a similar observation about relative age effects among players
in the Quebec Junior Hockey League. We published our findings in
English,1 and Simon and his colleagues published theirs in
French.2 This being a grand example of the twain not meeting, we did
not hear about each other for some years. When we did, we put on a joint
symposium on relative age at the 1993 conference of the Canadian Psychological
Association. The relative age effect, is strikingly evident in activities that are competitive and where performance is highly correlated with age and maturity. As noted above, the relative age effect in sport was first noted among elite level ice hockey players. These findings demonstrated that for major junior leagues and the National Hockey League, player birth dates decreased in frequency from January through December. It was theorized that this relative age effect arose from the consequences of grouping young boys for entry into organized minor hockey, thereby producing a one-year age range for the participants. As size, speed, and coordination are highly correlated with age, older players within the age-group will, on average, show superior performance. Thus, it can be said that maturity had been mistaken for ability by coaches, peers and the individuals themselves. The resulting expectations that are created for individual children creates a self-fulfilling prophecy that provides age-advantaged children with greater self-confidence and regard by others. The opposite will likely hold for those younger than their group-mates, with adjustments to poorer initial performance likely including lowered self confidence and self-esteem. One consequence that has been found is an increased drop-out rate for those disadvantaged by age in the past,3 suggesting that given the choice, younger children will seek to leave or avoid an activity in which their competitive position is hampered by their relative age. Predictably, the relative age effect has also been found in other competitive sports such as baseball,4 world class soccer,5 and American football.6 Some of our work has shown that the effects extend to emotional development7 and suicide.8 More |
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| Background (continued) | ||||||||
| It should be noted that schooling shares many of
the structural characteristics of children's sports programs. Children are age
grouped for entry into school, are rated according to achievement, and are
placed in different programs with different curricula and learning options
based on these measures of performance. In line with this logic, a large body
of literature has consistently reported a strong effect of the age of school
entry on academic achievement. For example, school children with a relative age
advantage are more likely to show higher achievement, to be placed in programs
for gifted children,9 and to be placed in more challenging
educational streams or classes.10,11 Children with a relative age
disadvantage, are more likely to be retained ("failed") for an additional year
in the same school grade,12 to be referred for psychological
assessment,13 and to be placed in a specialized group or provided
with a diagnostic label for remedial instruction.14,15 As a
consequence of these findings, many have suggested that parents should postpone
school entry for those younger children whose birthday places them near the
"cutoff" for their age group. The result of such action would place the
children in question among the eldest of their eventual classmates, rather than
the youngest. This contradicts an earlier tendency of parents to try and
arrange early admission for children who were actually too young to make a
particular cutoff.16 Theory. The proposed causal chain from birthdate to differences in achievement, self-regard, and suicide involves the following steps: First, relative age produces differences in achievement that are due to maturation, not ability. Second, these differences lead to variation in self-esteem and confidence. Third, low self-esteem and lack of self confidence are associated with a child's inability to compete with his or her classmates leading, respectively, to depression and hopelessness. Finally, depression and hopelessness, which are generally regarded as the essential ingredients of suicide,17,18 become precursors of self-harming behaviour. Gus Thompson Background References University of Alberta |
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References
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