[R] In factor analysis in the psych package, how can I work out which factors the columns in $scores relate to? How do I know what each of the scores is scoring?

[Brent Caldwell]

Dear Prof Carlson
Thank you very much.  As far as I can tell, factor.scores requires an object from class grm, itm, rason, or tpm; which I think are part of the irt package with which I am unfamiliar.
I had used the psych package to do the following factor analysis:
fa.11factors.rawdata <- fa(WISDMrawdataframe,nfactors=11)
# WISDMrawdataframe has 37 columns and 2408 rows, and contain 1051 rows that are NA (having NA in this dataframe allows the raw data to have the same length as my vector of ID numbers so I can work out which participants the data belong to)
fa.11factors.rawdata$loadings #on the computer screen this gives me the loadings with column names    MR4    MR3    MR2    MR6    MR7    MR5    MR1    MR8    MR10   MR9    MR11
fa.11factors.rawdata$scores # on the computer screen this gives me the scores with column names              [,1]       [,2]        [,3]       [,4]        [,5]       [,6]       [,7]       [,8]         [,9]      [,10]       [,11]
Am I safe in assuming that the scores in the first column relate to the loadings in the column called MR4?  
If this is a safe assumption, then I can work out which factor the scores relate to, by looking at which items load onto MR4    MR3    MR2    MR6    MR7    MR5    MR1    MR8    MR10   MR9    MR11
Thank you, I've taken your advice and cc'd this to Prof William Revelle
Thank you
Best wishes
Brent

-----Original Message-----
From: David L Carlson [mailto:dcarlson at tamu.edu] 
Sent: Thursday, 6 December 2012 10:33 a.m.
To: Brent Caldwell; 'r-help at R-project.org'
Subject: RE: [R] In factor analysis in the psych package, how can I work out which factors the columns in $scores relate to? How do I know what each of the scores is scoring?

Without seeing what options you have specified in your call to fa(), it is not possible to answer the question. There are detailed discussions in ?fa and ?factor.scores in the psych package, but for the final word you should probably contact the package maintainer: 

Package: psych
Version: 1.2.8
Date: 2012-08-08
Title: Procedures for Psychological, Psychometric, and Personality
        Research
Author: William Revelle <revelle at northwestern.edu>
Maintainer: William Revelle <revelle at northwestern.edu>

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r- 
> project.org] On Behalf Of Brent Caldwell
> Sent: Wednesday, December 05, 2012 2:53 PM
> To: r-help at R-project.org
> Subject: [R] In factor analysis in the psych package, how can I work 
> out which factors the columns in $scores relate to? How do I know what 
> each of the scores is scoring?
> 
> Hi
> I have used fa() to perform a factor analysis of a psychological 
> battery which is thought to have 11 factors.  I can identify which 
> factors the loadings relate to easily enough because I can see which 
> items are loading onto each of the columns in the $loading output.
> However, how can I identify which items or loadings are being used to 
> create each of the columns in the $scores output?  I have used 
> generalised linear models which have shown that some of the scores are 
> significant predictors of treatment outcome, but I can't work out 
> which of the 11 factors they are scoring?
> 
> when I export to csv the $loadings I get the following columns in this
> order:
>  MR4, MR3, MR2, MR6, MR7, MR5, MR1, MR8, MR10, MR9, MR11
> 
> When I export to csv the $scores I get the following columns in this
> order:
> V1, V2, V3, V4, V5, V6, V7, V8, V9, V10,V11
> 
> Are the scores in the column V1 derived from the loadings in column 
> MR1 ?
> Or are the scores in the first column of $scores (ie V1) derived from 
> the loadings in the first column of $loadings (ie MR4)?
> 
> Thank you very much for your guidance, and your patience with my 
> confusion Best wishes Brent
> 
> 
> Brent Caldwell, MBChB, DPH, MPH.
> Research Fellow
> Department of Medicine
> University of Otago, Wellington
> New Zealand
> U  brent.caldwell at otago.ac.nz
> b  04 918 6041
>    021 87 22 64
>   23a Mein Street, PO Box 7343, Newtown, WELLINGTON 6021, NEW ZEALAND
> brent.ower.caldwell
>   Zonnic study
> 
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