Brief Comparison - The Woodlands TX and Fayetteville-Manlius
This brief article demonstrates the method to compare inherent speeds of different XC courses in different sections of the nation ... Recently, I have been receiving e-mails asking the same question - "Is it really possible to compare the race speeds at very different courses around the country??" ... The most accurate answer is "Sometimes" ... When I attempt to evaluate race courses out-of-state where I don't know the runners or their individual abilities, I am NOT able to determine speed ratings most of the time ... For starters, I need full results (not just the top 10 or 20 finishers because I don't know the runners) ... Secondly, the race must have many runners of all abilities so statistical sampling is possible.
The Woodlands TX is currently the #3 Boys team in the nation ... a number of people asked me to rate them relative to the other top teams (I very rarely evaluate out-of-state races unless some NY teams attend due to personal time limitations), but since FM is involved in the comparison, I decided to do it and demonstrate the basic process used.
The Woodlands last race was the Chili Pepper CC Festival in Arkansas (10-16-2004) ... Full results are available ... and even better, full results are available for nearly 500 varsity runners ... this is more than adequate to meet the criteria required for an evaluation ... Here are process steps:
(1) merge the Chili Pepper results
(2) plot the Chile Pepper results on a graph
(Finish Position vs Race Time in seconds)
(3) scale and plot the Baseline race on the
same graph ... (scale means the finish position axes must match
lengthwise in terms of number of runners ... if one race has 500 runners
and another has 1000, the 500 and 1000 must line up ... to do this, you
could simply divided each finish position in the 1000 race by 2, so the
plotted positions would be 0.5, 1.0, 1.5 and so on)
(4) perform a graphical evaluation to determine if a comparison is reasonable
(5) either graphically or statistically, determine
the time difference between the two races
Here is the graph for the Chili Pepper CC Festival:
A quick look shows the two races appear very compatible (the slopes are very similar) ... the curved section of each line (the line being formed by the green data points) represent the "elite" and better "above average runners" (the Chili Pepper has more elite runners than the baseline) ... BUT the comparison is based on average runners that comprise the majority of data ... The red lines are drawn as corresponding to the average runners - the red lines are perfectly parallel - and the time difference between them is about 100 seconds indicating that the Chili Pepper race course was about 100 seconds faster than the baseline course (I used 99 seconds as the adjustment because it is a multiple of three).
To be valid, the 99 second adjustment requires the following assumption to be accurate ... "the average runners in the Baseline race are approximately equal in quality and speed to the average runners in the Chili Pepper race" ... Note that the "elite" runners (such as The Woodlands runners) are not considered in deriving the adjustment ... Experience in evaluating these types of graphs (plus the large number of runners in the Chili Pepper meet) indicates the assumption is valid with a reasonable degree of certainty.
The 99 second adjustment and the resulting adjusted times (plus speed ratings) are shown below: