From kyler at smu.edu  Thu Oct 15 21:15:15 2009
From: kyler at smu.edu (kyler at smu.edu)
Date: Thu, 15 Oct 2009 21:15:15 +0200 (CEST)
Subject: [Rd] Eigenvalue Bug in "psych" "principal" (PR#14010)
Message-ID: <20091015191515.3270B2831FE7@mail.pubhealth.ku.dk>

Full_Name: Kyle Roberts
Version: 2.9.2
OS: Windows XP
Submission from: (NULL) (129.119.244.130)


In 2.9.2, the Eigenvalues from a principal components analysis using "principal"
in the "psych" package no longer works. It still works in 2.8 and 2.7, but no
longer in 2.9.2. For example:

> library(MBESS)
> data(HS.data)
> library(psych)

> #### Subset the dataset to include only 8 variables
> new.data<-subset(HS.data, select=c(deduct, numeric, problemr, arithmet, 
  paragrap, sentence, wordc, wordm))

> pc2<-principal(new.data, nfactors=2, rotate="varimax")
> pc2
Principal Components Analysis
Call: principal(r = new.data, nfactors = 2, rotate = "varimax")
         item  PC1  PC2   h2   u2
deduct      1      0.68 0.52 0.48
numeric     2      0.82 0.69 0.31
problemr    3 0.45 0.54 0.49 0.51
arithmet    4      0.67 0.54 0.46
paragrap    5 0.84      0.76 0.24
sentence    6 0.89      0.83 0.17
wordc       7 0.76      0.65 0.35
wordm       8 0.81 0.30 0.75 0.25

                PC1  PC2
SS loadings    3.09 2.13
Proportion Var 0.39 0.27
Cumulative Var 0.39 0.65

Test of the hypothesis that 2 factors are sufficient.

The degrees of freedom for the model is 13  and the objective function was  0.36

The number of observations was  301  with Chi Square =  104.87  with prob < 
1.9e-16 

Fit based upon off diagonal values = 0.97
Measures of factor score adequacy             
                                              PC1 PC2
Correlation of scores with factors              1   1
Multiple R square of scores with factors        1   1
Minimum correlation of factor score estimates   1   1
> 
>   ## Eigenvalues
>   pc2$values
NULL

####################
It still works in the principal axis factoring package in "psych", but no longer
with "principal".



[Rd] Eigenvalue Bug in "psych" "principal" (PR#14010)
kyler at smu.edu