Danelien van Aalst at the University of Groningen in the Netherlands and her colleagues have investigated how relative age affects popularity among 14 to 15-year-olds in the Netherlands, Sweden and England. They collected survey data from 13, 251 students from the three countries.
Each teenager was asked to identify five of the most popular students in their class. The researchers then compared the popularity of each child to their age relative to that of their classmates. They discovered a connection; the older the student was, the more likely he or she was to be considered popular.
"A child enters school before or after a certain cut-off date and that determines how old or young you are relative to your year group. "says Danelien van Aalst. "We found that if you're born right after the cut-off date, making you one of the oldest members of your class, you're going to be popular.
They found that the same effect also applied at the year group level. Here, it was the children who were the oldest relative to all of their fellows in the year group一rather than just those in their particular class—that were the most popular.
All three countries showed almost the same pattern. However, at the year-group level, it was the most pronounced in England. At the classroom level, it was in the Netherlands that the pattern was the strongest. This is partly because the country has a system of grade retention- when students don't meet their academic requirements, their teachers will hold them back a year, which means they then are older than all the other classmates and often the most popular.
This relative age effect has been shown in other areas." Relative age has earlier been demonstrated to affect school performance—relatively older children do better in school, "says Herman van Werfhorst at the University of Amsterdam, who wasn't involved in the study. Similarly, previous research has shown that older children tend to be better at sports than younger students in the same year group.