Race results are determined solely on the number of laps run, which are multiplied against the USATF certified course mileage (Laps x 0.973 miles). A difference in mileage is likely a result of deviating from the course to go to the restroom, tent, car, meandering at aid station, partial/incomplete laps, not following the exact line of path our USATF course certifier used, margin for error of GPS devices, etc.