Accidents - correlation and causation?

Seen in Avweb's AvFlash:

[begin quote]
CRASH STATISTICS, FROM THE ASSOCIATED PRESS
According to the AP's research, pilots older than 50 were involved in
55.8 percent of accidents over a five-year period even though they
constitute only 36.8 percent of certificated pilots. And, apparently,
the
older a pilot gets, the greater the risk. Pilots between the ages of 50
and 59 had 26.4 percent of accidents, marginally higher than their
percentage of the pilot population, which is about 22.1 percent, but
those 60 and older had 23.6 percent of accidents even though they make
up
only 14.7 percent of certificated pilots. The research also determined
that those under 50 consistently had proportionately fewer accidents
throughout the five-year sample period. More...
[end quote]

The main article goes on to say that pretty much anything other than age
was not factored into the report.

I'm just wondering - yet another questionable analysis? (I have no axe
to grind, it's still a couple of decades until I'm considered 'an older
pilot')

In particular:
- In the set of pilots between 20 and 50, perhaps a larger proportion of
those pilots are professional pilots flying for the airlines, where
the accident rates are lower and 2-pilot crews are the norm.
- In the set of pilots aged 50 and over, perhaps many more flight hours
are being flown by this group in GA aircraft because (a) they have the
time and (b) they are more likely to have the money - since their time
and money are less likely to be soaked up by child-rearing.
- as AvWeb pointed out, perhaps older GA pilots (generally having more
money) are flying faster machinery that is more likely to result in a
fatality when the angle of arrival is too steep.

I'd like to see it normalised particularly for flight hours and limited
to GA pilots only before I could draw any conclusions at all for a study
such as this. I don't think it carries much weight at all.

--
Dylan Smith, Port St Mary, Isle of Man
Flying: http://www.dylansmith.net
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