When “where” is more important than “when”: Birthplace and birthdate effects on the achievement of sporting expertise

TLDR

The study investigates whether an athlete’s birthplace or birth month affects their probability of reaching professional sport. The authors compiled birthplace and birth month data for all American NHL, NBA, MLB, PGA players and Canadian NHL players, then used Monte Carlo simulations and chi‑square tests to compare birthplace distribution to census data and assess birth month uniformity. Results revealed that professional athletes are disproportionately from cities under 500,000, that a relative‑age bias exists in hockey and baseball but not in basketball or golf, and that birthplace factors have a stronger and independent influence on elite performance than relative age.

Abstract

Abstract In this study, we assessed whether contextual factors related to where or when an athlete is born influence their likelihood of playing professional sport. The birthplace and birth month of all American players in the National Hockey League, National Basketball Association, Major League Baseball, and Professional Golfer's Association, and all Canadian players in the National Hockey League were collected from official websites. Monte Carlo simulations were used to verify if the birthplace of these professional athletes deviated in any systematic way from the official census population distribution, and chi-square analyses were conducted to determine whether the players' birth months were evenly distributed throughout the year. Results showed a birthplace bias towards smaller cities, with professional athletes being over-represented in cities of less than 500,000 and under-represented in cities of 500,000 and over. A birth month/relative age effect (in the form of a distinct bias towards elite athletes being relatively older than their peers) was found for hockey and baseball but not for basketball and golf. Comparative analyses suggested that contextual factors associated with place of birth contribute more influentially to the achievement of an elite level of sport performance than does relative age and that these factors are essentially independent in their influences on expertise development.