Running metric

It's been in the back of my mind for some time now; I've been vaguely aware of its general consistency. In most races, my finishing position percentiles have seemed to be fairly close to each other, whether relative to the entire race field, men only, or my age group. The pattern has seemed to persist, regardless of the type of race or size of field. Curiosity piqued, I went through my race results and did some quick spreadsheet work (See plot). The x-axis is my finishing positions, and the y-axis is the total number of runners, whether of the

entire field, men only, or my age group. The blue trend line, with an R-sq = 0.6577, suggests that the size of a race field (all groupings, all types of races) is a fair indicator of my finishing position. This result also suggests that the population distribution of race paces is fairly consistent, at least for the same geographical region in which most of the races took place, and reflects the consistency of my pace across races. There are some uncertainties in my statistics here. For example, I mixed the results based on the entire field, men only, and age group. Also, for some of the larger races that had fields in the 10s of thousands, I scaled the results to be less than a thousand, to fit in the plot.

In any case, what's of more interest to me are the red, dashed lines, which are the 50th to 90th percentiles. So, if my result fell on the 50th percentile, then 50% of the field crossed the finish line after I did. The blue trend line is just above the 50th percentile, which accords with my general vague sense, over the years, that I usually finish near the bottom of the top half of the field. But, as the data show, there are also some outliers that are of higher percentiles (a few near the 90th--must have been relatively slow fields!). This is interesting because I can use the location of the trend line relative to the percentiles as a metric for my running progress. I'd be interested to know what you use as metrics.