In ranking the top 25 Ironman triathlons by degree of difficulty, average finish time is the primary ranking criteria. The question has come up, particularly about races that experience vastly differing conditions from one year to the next (such as Louisville, Wisconsin, Kona), how are DNF rates factored in?
Our position has been that tougher conditions lead to slower finish times, which should also result in higher DNF rates. Similarly, perfect conditions tend to result in faster finish times and fewer DNFs. As such, the average finish time, by definition, captures the implied impact of DNF rates. As shown in the chart above, plotting Kona DNF rates and Average finish times from 2002 to 2010 yields a result that supports this view. For more. see our complete Ironman Kona Coverage or see our Site Map.