Wednesday, August 3, 2011

Predicting finishing times

I would like to know how others go about predicting their finishing times for trail ultras, especially those that they have never run.

Recently, I predicted it would take me 12 hours to finish Voyageur. I ended up finishing in just under 11 hours. While I am certainly satisfied with the time, I can't help but think I possibly could have done better if I hadn't straddled myself with the lower expectations. There certainly is an element of self fulfilling prophecy in predicting race times, at least if those predictions are relatively conservative. You predict a certain time, so you go out at that pace, and lo and behold, you finish near the predicted time.

One strategy I have used is to look at the previous results for a race, and shoot for the median time. I have noted from my previous races that I generally finish right in the middle, near the median. So for example, before running the Wild Duluth 50K last year I looked at the 2009 finishing times, noted that there were 58 finishers and the 29th runner finished at 7:18. I used that as a ball park for my own time, and sure enough, finished in 7:05. But again, I can't help but wonder if I could have done better if I had predicted a 6:15 instead.

It is worth noting that this strategy works best with more data. Using a single year's race data is of limited use unless the weather and trail conditions are going to be identical, and there was a relatively large number of finishers. I just signed up for the Marquette 50 mile race on Aug. 20th. There were only 9 finishers last year. Number 5  finished in 11:32, but number 4 finished at 10:08.

This strategy is also limited by my own self confidence. I see my self as a median runner. Maybe if I saw myself as a top 25% runner my times would improve?

Well. What are your strategies for predicting finishing times?


  1. The most common method people use is the "Relative Race Finish Times" at; it's pretty good. Of course, I've managed to complicate matters and have found that the cube root of finishing places plotted versus finishing times for most races have sections that approximate straight lines and these are comparable between races (it's even more complicated than that sounds).

  2. Thanks Steve. I have just spent the better part of my morning playing around with this tool. Nice!