## Uniqueness calculation in EFA

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## Uniqueness calculation in EFA

Hi, in a five factor EFA solution the uniqueness calculation seems a bit off, not sure why. Hand calc gives me a uniqueness of 0.66 for a promax rotated solution but the jamovi displayed value is 0.74. Hand calc of the unrotated solution is correct, so I'm not sure why rotated factor loadings don't add up to displayed uniqueness. Using jamovi 0.9.5.5.
David
ps omv attached
Attachments
bfi_sample.omv
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

Hi David,
So by default we use "Minimal Residuals" as the factor extraction method (just like the R package "psych" that we use in the background). However, "factanal" uses maximum likelihood as the extraction method. If you change the extraction method to maximum likelihood, the uniqueness should be the same again.

Cheers,
Ravi

Ravi

Posts: 149
Joined: Sat Jan 28, 2017 11:18 am

## Re: Uniqueness calculation in EFA

Hi Ravi, maximum likelihood also gives 0.66 uniqueness for a five factor promax rotated solution (hand calc) - but the displayes uniqueness is 0.74 (jamovi 0.9.5.
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

jamovi 0.9.5.8 ... not sure why the shades appeared!
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

jmv syntax shows nFactors = 2 but five are extracted using parallel method...could this be something to do with it? See attached.
Attachments
Screenshot 2018-11-23 at 12.14.54.png (164.48 KiB) Viewed 2356 times
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

..answering my own question, NFactors = 2 or NFactors = 5 in jmv syntax doesn't change things...
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

But it does match the R result you calculated using 'factanal' now right?

Ravi

Posts: 149
Joined: Sat Jan 28, 2017 11:18 am

## Re: Uniqueness calculation in EFA

Using factanal handcalc uniqueness = 0.66 but displayed = 0.74, just like in psych. Probably something happening that I don't understand...I had thought that rotated factor loading should still sum to same communality / uniqueness as unrotated?
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

Further digging shows that with orthogonal rotation (varimax) factor loadings combine correctly to displayed uniqueness, but not for oblique rotation (promax). Extraction method doesn't seem to make a difference.
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

## Re: Uniqueness calculation in EFA

aah, pattern vs structure matrix!! Sorry I'm a bit rusty on fa
David

Posts: 30
Joined: Wed Jun 13, 2018 10:18 am

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