R help - Jan 2008 - OT: single measure of (group) correlation with more than two vectors?

Hello, 

I have a survey in which a number of people rated a
set of items on a 
1..5 scale.  I believe it would be desirable to argue
that the
people's responses are correlated, and thus that the
rating task
makes sense to people.

Is there a standard approach to this?   With only 2
people,
the correlation coefficient between their responses
would
be an interpretable number, (though probably there is
some
stronger way to assess whether the results are
_significantly_ correlated).

With N>2 people, there is the correlation matrix, but
it does not
give a nice single number.  Thinking, the determinant
of
the matrix of response vectors might be a possibility,

since it will be low if the rows are correlated.
Though, it should be normalized somehow to be
interpretable.

Is there a standard approach to this problem?

Thanks for any advice




     
____________________________________________________________________________________
Be a better friend, newshound, and

What you may want is a measure of inter-rater
reliablity though what you are discussing is not the
way it is normally used. 
  Try googling "inter-rater reliability" or have a
look at a text book like  Introduction to classical
and modern test theory  Linda Crocker and James
Algina.
New York : Holt, Rinehart, and Winston, 1986.

--- context grey <mobygeek at yahoo.com> wrote:
> Hello, 
> 
> I have a survey in which a number of people rated a
> set of items on a 
> 1..5 scale.  I believe it would be desirable to
> argue
> that the
> people's responses are correlated, and thus that the
> rating task
> makes sense to people.
> 
> Is there a standard approach to this?   With only 2
> people,
> the correlation coefficient between their responses
> would
> be an interpretable number, (though probably there
> is
> some
> stronger way to assess whether the results are
> _significantly_ correlated).
> 
> With N>2 people, there is the correlation matrix,
> but
> it does not
> give a nice single number.  Thinking, the
> determinant
> of
> the matrix of response vectors might be a
> possibility,
> 
> since it will be low if the rows are correlated.
> Though, it should be normalized somehow to be
> interpretable.
> 
> Is there a standard approach to this problem?
> 
> Thanks for any advice
> 
> 
> 
> 
>      
>
____________________________________________________________________________________
> Be a better friend, newshound, and
> 
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