A relative age effect in NASCAR.

The distribution of birth months and quarterly birth months of NASCAR drivers (N = 1054) showed significant differences in quarterly birth month distributions between drivers. The highest percentage (27.1%) of drivers were born April-June. Data for the other three periods ranged from 23.6% to 24.7%. The finding was discussed in the context of the "relative age effect" occurring in sports wherein competitors become eligible for participation by age at a specific cut-off date.