Jack,
Great job!
Another interesting measure of the biases of the sample of respondents
is that while only about 5% of soaring pilots fly in contestes, 28% of
your respondents do.
Al
Discus B PG
DrJack wrote:
John Roake, Chairman of the International Gliding Commission's
Membership Committee, has stated (see on-line Gliding Magazine at
http://www.glidingmagazine.com/Featu...cle.asp?id=400) that based
on newly revised FAA statistics the SSA represents less than 50% of
sailplane pilots in the USA. So I found it interesting that in a
recent poll of BLIPMAP users, of the 430 respondents who listed
themselves as a "Sailplane" pilot the percentage who also said they
were SSA members was _91%_. Of course any statistic can be biased
and knowing how different statistics should be interpreted can be
tricky, but still 91% differs greatly from "less than 50%". I expect
that BLIPMAP users tend to be more active pilots and also more likely
to be XC/contest pilots than the "average" soaring pilot. It's also
possible that those BLIPMAP users who took the time to respond are
more "group" oriented than those who did not - but with a 30%
participation, there would have to be a huge opposing bias in the
non-participating pilots to get down to a 50% overall SSA-member
level. FWIW, my conclusion is that the number of _active_ soaring
pilots who are also SSA members is much greater than 50%, so the pool
of non-SSA soaring pilots which might be used to increase SSA
membership is not nearly so large as Roake's statement would suggest.
A summary of that survey is now available on-line at
http://www.drjack.info/BLIP/INFO/SUR...3.summary.html
Jack