About
Racecast puts every cross country and track result on one comparable scale, so a 5K on a muddy course in Minnesota and a 3200 on a fast track in California can be read as the same kind of number.
What a rating is
A speed rating is a race, corrected for everything about it that was not the athlete, and expressed against the field the athlete competes in. 100 is the mean of that pool; higher is faster. Real values run roughly 30 to 170.
Because the scale is pool-relative, a rating is only meaningful within its pool. A 140 in high school boys and a 140 in middle school boys are not the same performance — each is measured against its own field.
How a result becomes a rating
- Distance. Every time is converted to a 5K-equivalent, using a curve fitted per pool rather than a fixed formula. This is because older runners are a lot better at longer distances than younger runners. However, this does lead to some less than ideal conversions for longer distances.
- Geometry. Track results are corrected for the track itself: length, banking, indoor or outdoor. These corrections do not show in course difficulty, although they may show a residual affect.
- Era. Times drift across decades due to shoes, surfaces, and training. The era correction is what lets a 2010 season sit beside a 2026 one.
- Weather. Heat and wind are corrected where the conditions are known.
- The course. Every venue gets a difficulty solved from athletes who raced both there and elsewhere, the whole corpus at once, not course by course. This is what makes two races on different courses comparable at all. Courses with not enough links are forced to a rating of 0.0. The average XC rating is about +0.01, and for TF about -0.015.
Where it is still wrong
One race is not a season
The same athlete, at the same venue, in the same season, varies by about 3.3% race to race — roughly 4 rating points. That is not measurement error; it is what racing is like. It is why the default board ranks athletes by their season average and the single-race board is labelled performances rather than athletes.
A great race by an ordinary athlete will outrank an ordinary race by a great one. On a performance board that is correct. As a ranking of athletes it would be wrong, which is why they are two different boards.
Thin courses get a default
A venue that hosted one race, with athletes who race nowhere else, does not contain enough information to solve a difficulty for. Those get the sport's average rather than a confidently wrong number.
Some athletes are in the wrong pool
Level is inferred from grade, school and the races an athlete actually ran. Where those disagree — a ninth grader at a K-12 school, an eighth grader running varsity, a high school senior on a college start list — the inference can land on the wrong side. Since the scale is pool relative, a wrong pool means a number on the wrong scale. If you spot one, tell us.
The data
Over 200 million stored results, with 59M rated results across 73K courses and 37 years, from middle school through college. Results are aggregated from public results databases and re-rated from scratch on every run — the ratings here are not taken from anywhere, they are computed.
Found something wrong?
Wrong ratings are the most useful thing you can report, and specific ones are more useful than general ones. Report an issue.