Does JAMOVI use the KR-20 formula for alpha?

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Mark9999
Posts: 1
Joined: Tue Jul 31, 2018 1:53 am

Does JAMOVI use the KR-20 formula for alpha?

Post by Mark9999 »

Hi
When Jamovi is calculating Cronbach's alpha for internal consistency (reliability) - does it switch to using the KR-20 formula (Kuder-Richardson 20) when it detects that the measures are dichotomous? My understanding is that SPSS does this (because Cronbach's alpha isn't appropriate for dichotomous variables) - and just wondering if JAMOVI did the same?
Couldn't find an answer to this elsewhere.
Thanks!
Mark
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jonathon
Posts: 2613
Joined: Fri Jan 27, 2017 10:04 am

Re: Does JAMOVI use the KR-20 formula for alpha?

Post by jonathon »

hi mark,

jamovi uses the psych package to perform it's reliability calculations:

https://github.com/jamovi/jmv/blob/mast ... ty.b.R#L38

you could read up on what it does. this might be a good starting point.

https://www.rdocumentation.org/packages ... pics/alpha

cheers

jonathon
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