Re: [Paddlewise] Rudder redux

On 7/2/07, Nick Schade <nick_at_guillemot-kayaks.com> wrote:
>
>
> It is very good at producing anecdotal evidence, but not for gathering
> accurate data. It is a start, and if you want to do it, feel free, the
> results will be interesting, but very arguable.
>

As near as I can tell, everything on this forum is very arguable.


> If you now repeat that test with everyone you know each paddling every
> kayak you can get your hands on you can get a pretty good set of data for
> how kayaks generally performs with and without a rudder.
>

Yup. Wouldn't that be an interesting set of data though? And not at all
anecdotal.


> For the record, I think rudders can help people paddle faster, I just
> don't think Caffyn's data is solid evidence of that opinion.
>

I don't believe I ever said that I thought Caffyn's data is solid evidence
that rudders can help people paddle faster. I just said it was valid
evidence, that it was emprical evidence and that it was not anecdotal.

And, for the record, my Nimbus Telkwa is the only kayak I've ever owned with
a rudder and the first one I ever paddled with a rudder. I do believe that,
over a point-to-point course, a rudder can help me reduce effort. Whether I
put that savings into going faster or going farther or stopping to play is
up to me. But I've never thought that a rudder in-and-of itself is either a
religious experience or a device invented by Satan. It's a tool that can be
used if one desires.

 ICF sprint racing kayaks tend to have rudders. I would be shocked if there
> wasn't testing done to demonstrate that they are beneficial for racing.
> However, just observing that the ICF boats use them is itself anecdotal
> evidence, not reliable data.
>

Yup. But the results of races between kayaks with rudders and without them
would not be anecdotal, it would be raw data subject to analysis. Generally
statistical analysis.

> The data is not anecdotal. But all the opinions are.
>
>
> "Anecdotal" refers to evidence based on reports of specific individual
> cases rather than controlled, clinical studies. Caffyn's report is the very
> definition of "anecdotal".
>

Well now we're throwing in a new term. I don't think anyone has referred to
Caffyn's "report". A report certainly can be anecdotal ("James reported that
he saw a guy in a kayak with a rudder going faster than one without.") but
since it's the data itself - the raw, unadulterated written accounts of how
many miles were paddled each day - we're talking about here, then that's not
anecdotal.

Nor would a statistical analysis of that data be anecdotal.

Anecdotal evidence is generally held to be that given by untrained observers
or hearsay ("I heard bob said he went faster with a rudder"). Caffyn's data
(not his "report" - whatever that is) is a written record of miles travelled
over a long period of time set down by an expert in the field. So when
Caffyn states that he thought the rudder made him go faster that may be
anecdotal. But when he says that the statistics indicate that he went faster
with a rudder it's not anecdotal. But, of course, one can do a lot with
statistics.

It's often held that one patient reporting a side-effect of a medicine is
anecdotal; but when 1,000 patients report the same side-effect that's no
longer anecdotal.

And evidence does not have to be only from "controlled, clinical studies" to
be valid, empirical data. The North American bird count is an example.

We all seem to be caught up in a trap in which only data from something that
was measured is valid when, in fact, science is full of emprical studies
made by self-taught experts. Geology is one. Zoology is another.


Craig Jungers
Royal City, WA
***************************************************************************
PaddleWise Paddling Mailing List - Any opinions or suggestions expressed
here are solely those of the writer(s). You must assume the entire
responsibility for reliance upon them. All postings copyright the author.
Submissions:     PaddleWise_at_PaddleWise.net
Subscriptions:   PaddleWise-request_at_PaddleWise.net
Website:         http://www.paddlewise.net/
***************************************************************************