Does JAMOVI use the KR-20 formula for alpha?

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by Mark9999 » Tue Jul 31, 2018 2:02 am

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.
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by jonathon » Thu Aug 02, 2018 10:52 pm

hi mark,

jamovi uses the psych package to perform it's reliability calculations: ... ty.b.R#L38

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


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