Place but not Date of Birth Influences the Development and Emergence of Athletic Talent in American Football

The purpose of this study was to examine the birthplace and relative age effects in National Football League (NFL) players. The place and date of birth of NFL players in the United States were analyzed with Monte Carlo simulations to determine if either factor was predictive of the probability of reaching the elite level in this sport. Consistent with previous findings on professional North American athletes in baseball, ice hockey, basketball, and golf, players born in cities with populations of less than 500,000 were significantly over-represented in the NFL, whereas players born in cities with populations over 500,000 were significantly under-represented. Unlike many other sports, no relative age effects were found for the NFL. Small cities, in particular, appeared to possess characteristics that facilitate the development and/or emergence of athletic talent in American football. Possible psychosocial factors mediating the birthplace effect are discussed as are implications for the development of sporting expertise.

When “Where” is More Important Than “When”: Birthplace and Birthdate Effects On The Achievement Of Sporting Expertise

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.