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Re: st: Re: Polychoric PCA error message
From
"JVerkuilen (Gmail)" <[email protected]>
To
[email protected]
Subject
Re: st: Re: Polychoric PCA error message
Date
Mon, 25 Feb 2013 19:49:56 -0500
On Sun, Feb 24, 2013 at 8:46 PM, Nick Cox <[email protected]> wrote:
> My guess is that Jay meant Pearson correlations as calculated by -correlate-.
Yes, that's right. Polychorics are nice in theory but they're unstable
for many reasons already discussed. An ordinary Pearson correlation
will often tell you quite a bit. So for instance, if one is massive
and the rest are quite a bit smaller, you will almost certainly have
issues. Also look at the two way tables. You can usually predict
problems that way.
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