Your Garmin Vs. The Certified Course Measurement: Why They May Not Match

If I had a dollar for every time someone posted a comment in a running or racing discussion board or on a race's Facebook page that their Garmin's mile measurement didn't match the certified course distance, I'd be a very rich person.  Or I'd spend all the money on race fees.  Either way, it's a common discussion point.

The short answer is: 99% of the time, no, your Garmin's registered distance will not match the distance of your certified course, regardless of the course distance.
No...