[R] Running Omega in R
John Smith
jSmith.Coursera at outlook.com
Mon Jan 16 18:38:14 CET 2017
Hi David
Thank you for your feedback
I didn’t realise you couldn’t implement omega on a single factor
This definitely makes sense the more I read on it
Thank you all very much for your time
From: David L Carlson
Sent: Monday 16 January 2017 16:43
To: peter dalgaard; Rui Barradas
Cc: John Smith; r-help at r-project.org; revelle at northwestern.edu
Subject: RE: [R] Running Omega in R
I get an additional error message when I run your example so perhaps your version is not the current (1.6.12) one?
Loading required namespace: GPArotation
Failed with error: ‘there is no package called ‘GPArotation’’
Error in omegah(m = m, nfactors = nfactors, fm = fm, key = key, flip = flip, :
I am sorry, you need to have the GPArotation package installed
Then I get a great deal of error output followed by the one you list. The first error is
"Omega_h for 1 factor is not meaningful, just omega_t" (repeated 174 times). I'm copying the package maintainer as this seems like overkill.
Your problem is addressed in the first line of the manual page for omega:
"McDonald has proposed coefficient omega as an estimate of the general factor saturation of a test. One way to find omega is to do a factor analysis of the original data set, rotate the factors obliquely, do a Schmid Leiman transformation, and then find omega. "
You cannot rotate a single factor so you cannot compute omega.
-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of peter dalgaard
Sent: Sunday, January 15, 2017 2:27 PM
To: Rui Barradas <ruipbarradas at sapo.pt>
Cc: John Smith <jSmith.Coursera at outlook.com>; r-help at r-project.org
Subject: Re: [R] Running Omega in R
> On 15 Jan 2017, at 20:57 , Rui Barradas <ruipbarradas at sapo.pt> wrote:
>
> Hello,
>
> I no nothing about package psych so if you ask whether this is the wrong list you can always try
>
> maintainer("psych")
> [1] "William Revelle <revelle at northwestern.edu>"
...although publishing a package is not the same as issuing a blank cheque for free support, so you may want to dig a little deeper first.
I'd check the documentation for whether the data are in the right format. In particular, can "m" be a data frame? If it wants a matrix, you probably need to give it one (m=as.matrix(construct) should do it).
-pd
>
> Hope this helps,
>
> Rui Barradas
>
> Em 15-01-2017 12:32, John Smith escreveu:
>> Hi,
>>
>> I opened a question on stack overflow I’m hoping this mailing list can help with.
>> I have a dataset below (this is made up but produces the same error I am getting)
>>
>> structure(list(Q1 = c(4, 5, 3, 5, 4, 5, 3, 5, 5, 5, 6,
>> 3, 5, 4, 6, 5, 5, 6, 7, 4, 5, 5, 3, 4, 4, 5, 4, 3, 5, 4, 5, 5,
>> 6, 6, 3, 6, 3, 4, 4, 4, 6, 5, 3, 2, 6, 6, 4, 5, 4, 3, 6, 4, 4,
>> 5, 6, 2, 4, 3, 4, 6, 4, 6, 4, 5, 5, 6, 4, 6, 5, 5, 4, 5, 6, 6,
>> 2, 5, 4, 3, 4, 4, 4, 6, 3, 3, 5, 4, 4, 4, 5, 5, 5, 3, 6, 6, 6,
>> 6, 5, 4, 3, 5), Q2 = c(7, 4, 4, 4, 4, 6, 6, 6, 7, 6, 5,
>> 6, 5, 4, 5, 6, 6, 6, 7, 5, 4, 4, 6, 6, 4, 4, 6, 2, 6, 5, 4, 6,
>> 4, 6, 6, 6, 5, 4, 4, 4, 4, 3, 3, 4, 4, 4, 4, 6, 2, 6, 6, 5, 4,
>> 6, 6, 4, 4, 7, 6, 5, 5, 5, 5, 6, 5, 5, 4, 5, 5, 5, 4, 6, 7, 5,
>> 5, 5, 6, 5, 6, 5, 6, 7, 2, 6, 5, 7, 3, 5, 5, 3, 3, 3, 7, 4, 5,
>> 6, 6, 6, 5, 7), Q3 = c(5, 4, 5, 6, 4, 4, 5, 4, 2, 6, 5,
>> 5, 5, 5, 7, 5, 5, 6, 7, 6, 3, 6, 6, 6, 5, 6, 6, 5, 5, 4, 5, 5,
>> 6, 6, 5, 6, 5, 5, 4, 4, 6, 4, 4, 4, 4, 4, 4, 5, 5, 4, 5, 5, 4,
>> 3, 5, 4, 5, 6, 6, 6, 4, 5, 5, 5, 6, 4, 5, 5, 7, 4, 5, 6, 6, 5,
>> 5, 3, 3, 5, 4, 6, 5, 5, 1, 3, 5, 3, 2, 5, 4, 6, 6, 6, 6, 4, 6,
>> 3, 6, 6, 6, 5), Q4 = c(6, 6, 4, 7, 4, 6, 7, 6, 7, 6, 6,
>> 6, 5, 7, 7, 6, 6, 5, 7, 7, 6, 6, 7, 7, 6, 6, 6, 5, 6, 7, 5, 6,
>> 7, 5, 4, 6, 4, 3, 6, 4, 6, 6, 6, 3, 5, 7, 5, 6, 4, 6, 7, 6, 7,
>> 4, 6, 3, 5, 7, 5, 4, 6, 6, 4, 6, 5, 5, 5, 5, 7, 7, 7, 6, 6, 6,
>> 5, 6, 6, 4, 5, 7, 6, 7, 3, 5, 6, 5, 6, 5, 5, 7, 7, 6, 6, 2, 7,
>> 6, 6, 7, 7, 5)), .Names = c("Q1", "Q2", "Q3",
>> "Q4"), row.names = c(NA, 100L), class = "data.frame")
>>
>>
>> When i run Cronbach Alpha with R i get a result
>>
>> psych::alpha(construct,
>> na.rm = TRUE,
>> title = 'myscale',
>> n.iter = 1000)
>>
>>
>> When i run Omega using R i get the following error message
>>
>> "Error in fac(r = r, nfactors = nfactors, n.obs = n.obs, rotate = rotate, : I am sorry: missing values (NAs) in the correlation matrix do not allow me to continue.
>> Please drop those variables and try again. In addition: There were 50 or more warnings (use warnings() to see the first 50)"
>>
>> psych::omega(m = construct,
>> nfactors = 1, fm = "pa", n.iter = 1000, p = 0.05,
>> title = "Omega", plot = FALSE, n.obs = 100)
>>
>>
>> Stackoverflow Link: http://stackoverflow.com/questions/41533231/running-omega-with-psych-library-in-r?noredirect=1#comment70278453_41533231
>>
>> If I have the wrong mailing list, could you direct me to the appropriate one (I’m aware it might not be an R issue but more of a stats question)
>>
>>
>>
>> Thank you for your time
>>
>>
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
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Office: A 4.23
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