How We Rank A Race’S Difficulty


I. Collect data and extract attributes

First, we collect a variety of data about the course, the majority of which comes from verified GPX files. Then, we extract certain attributes, like average elevation and gain per mile (GPM).

II. Compare attributes among races

Once we have a set of attributes, we simply rank them in ascending/descending order. To capture degrees of difference among races, we rank attributes based on a percentage of the maximum.

III. Assign a weighting to attributes

This is the subjective part. We assign a relative weighting to each attribute. The weightings sum to 100% for a given race. For example:

  • Total Ascent: 10.0%

  • Gain per Mile: 35.0%

  • Average Elevation: 25.0%

  • Average Temperature: 15.0%

  • Tallest Climb: 10.0%

  • “Unique” Miles: 5.0%

Recognizing that the attribute weightings are entirely subjective, we’re planning to let runners set their own weightings to make Turnsheet as personalized as possible. Some runners perform well in heat, while others excel at climbing.

IV. Calculate blended difficulty score