bdrude- You can call it whatever you want. Let's just be straight forward and just call it a person's fastest time over a certain distance. Even certified courses vary in true length (8k and 5 miles are considered the same for record keeping purposes even though 8k is about 50 yards shorter). Certified courses can have different start and finish locations, resulting in a net loss or gain in elevation. Boston is certified, but because it is point to point, the times can be recognized as world best, but not world records. Some certified courses are flat, some rolling, some have brutal hills to deal with, or are run in less than optimal weather conditions that reflect in times, but not effort. There is a margin of error in course measurement. Courses that start and finish within a certain distance of each other can be recognized for world records even though there may be an acceptable loss in elevation. Every course I have ever laid out was at least as long as advertised meaning they were all long within the acceptable range. The track does not lie.