[R-sig-eco] missing data in PCA
Jari Oksanen
jari.oksanen at oulu.fi
Fri Apr 3 07:55:20 CEST 2009
On 03/04/2009, at 00:32 AM, Jason S wrote:
>
> Dear all,
>
> I was wondering if you have good options to deal with missing data
> on a PCA in R. I guess I could simply delete those cases, but I
> think there should be better options in terms of predicting them.
> Any hints?
>
Howdy,
There may be better ways, but they are not easy... Check paragraph on
missing data in multivariate task view. This lists several
alternatives of multiple imputation data. About a year ago I tried
some of them for multivariate analysis, but that was not quite
straightforward. The problem was summarizing multivariate results.
Things may have been changed since then, and there may be some canned
routines.
Here is one link to multivariate task view (but you can use a mirror
close to you):
http://cran.r-project.org/web/views/Multivariate.html
One thing you should remember: do not replace missing values with means.
Cheers, Jari Oksanen
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