## 4 mile

The WAVA standards do not include a 4 mile table, but one can be added
by using the 5 mile WAVA standard time to predict a 4 mile time, and
then interpolating 5K and 8K age correction factors to obtain an
appropriate age correction factor for 4 miles.
The reason for doing so is that 4 miles, an oddball distance, is a common
event in Central Park, because the geography of the park makes it easy to
stage 4 mile races.
The geometric center
of 5 and 8 is about 6.3, the arithmatic center is 6.5, so I figure that
splitting the difference and taking the midpoint is reasonable, and that
is how I interpolate the age correction factors.

Note that my table will give different results than the NYRRC age graded
score (but I believe I'm right and they're wrong).

Here's a sample calculation that illustrates why I think NYRRC are wrong.
To get the correction factor
for a given age, one divides the age graded time in seconds by the net time in seconds.
To proceed, we need
some results from a 4 mile race
and the NYRRC age graded times (select M55-59).

Take the first result, age 57:

(23*60.0+19)/(27*60.0+42) = 0.84175

This is less than the 5k correction factor for age 57 (0.8419)
But take a result for age 55 (fourth place):

(26*60.0 + 8)/(30 * 60.0 + 27) = 0.85823

which is part way between the factors for 5k (0.8570) and 8k (0.8601).
It's actually closer to the 5k correction factor (closer than you'd
get even with a linear interpolation) and hence still looks wrong, but
at least it's somewhat less wrong.

### So What Does This Mean ???

For people in the open age groups, it means absolutely nothing, because
there are no age corrections for you. THe "gold standard" time I use
is the same as the one used by NYRRC.
In the above example, the 57 year
old competitor's rating dropped by 0.3% when the calculation was performed
using my correction factors (sorry Bob).