**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: |