FAT refers to electronic timing systems that automatically start when the gun fires (triggered by sound or sensor) and stop when the athlete crosses the finish line beam. FAT is accurate to 1/100th of a second and is required for all record attempts and major competitions.

Hand times are faster because human timers have a reaction delay when starting and stopping the watch. The starter typically anticipates the gun (starting late), and there's reaction time when stopping at the finish. This averages about 0.24 seconds for sprints.

For sprints (100m, 200m, hurdles): add 0.24 seconds to convert hand to FAT. For middle distance (400m+): add 0.14 seconds. These are the NFHS and NCAA standard conversion factors.

Yes, but with caution. Many pre-1977 world records were hand-timed. Adding the conversion factor gives an approximate FAT equivalent, but hand timing was often generous, so comparisons are imperfect.

The timing error is similar regardless of race length, but it becomes a smaller percentage of the total time. Additionally, finish line timing is often clearer in longer races as athletes are more spread out.