Runners have always debated the difficulty of different marathon courses. Some feel Boston is difficult, yet it has a significant net elevation loss. Some feel Steamtown is easy, but it has a significant ascent at the end. Course Performance has found the way to objectively rate each course based on its elevation profile, and it is not as easy of net elevation change.

Course Performance has developed advanced software algorithms that account for the placement of hills throughout a course in order to determine the true course difficulty.

A course's difficulty is not absolute. Each athlete has a different threshold for hill running, and a different threshold for speed. By taking into account an athlete's efficiency, Course Performance personalizes a race's difficulty.