But, there are certainly many different types of chip-timing...some just ok and some stellar, and lots in between. But, just for a summary of these (that I've seen so far), here is a ranking (from worst to best):
Scanned - Everyone starts at the same time (gunshot), and when you pass the finish line, your chip is scanned (like the hand-held scanners you see in grocery stores). In this case, to get the best representation of your time, you must start at the front of the start line, and also once you cross the finish line, there should be no pause in getting your chip scanned. Both are impossible, but significant deviations can be mitigated. These chips are often imbedded into your bib.
Gun Shot (No Chip-Timed Start) - Everyone starts at the same time (gunshot), and when you pass the finish line, your chip is scanned by the mat below your feet. In this case, to get the best representation of your time, there should start at the front of the start line. If you start near the back, you will you encounter a ton of congestion and it may take you a significant amount of time simply to cross the start line. These chips are often tied to your shoelaces.
Net Time (Chip-timed start and chip-time finish) - The gunshot is heard, but your "starting time" does not start ticking until you cross the start line. Similarly, the "finish time" does not stop until your cross the finish line. This is the best representation of your personal "net" time. These chips are often tied to your shoelaces.
A few things to note...
- USATF's standards are based on gunshot when determining the overall winner and/or top awards for age/gender. This is the reason why even great huge amazing races usually seed the best runners to the front of the line.
- Just because there is a mat at the starting line, don't assume that your "net" time will be recorded. I made this assumption once and it was very disheartening. If you think you are going for a PR, got to the front and then when you pass the start line, just make sure you are out of the faster runner's ways.
- Oftentimes, your overall placement/time and your "net" time will be available in the official online results, but not always....look at prior year's race results to see how they were presented.