Re: Appropriate to use Cronbach Alpha on a Yes/No scale

Posted by statisticsdoc on Nov 03, 2011; 3:50pm
URL: http://spssx-discussion.165.s1.nabble.com/Appropriate-to-use-Cronbach-Alpha-on-a-Yes-No-scale-tp4961283p4961441.html

Mark,
You will want to use the Kuder-Richardson 20 formula for dichotomous scales (alpha is a generalization of the KR 20). If you are getting low reliability, look at the item total correlations. Items may have low item-total correlations for a variety of reasons. The item might happen to have very little variability in your sample (so perhaps you need a more diverse sample). The item may have been mistakenly scored in the wrong direction (it happens sometimes). The item might not have a very strong relationship with the construct under investigation (dropping the item will increase internal consistency). If your internal consistency is so low, perhaps you should consider the possibility that the items measure multiple dimensions (which would lead us to a discussion of factor analysis with dichotomous items).
HTH
Stephen Brand, Ph.D.
www.StatisticsDoc.com

www.StatisticsDoc.com

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From: Mark Webb <[hidden email]>

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Date: Thu, 3 Nov 2011 16:51:52 +0200

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Subject: Appropriate to use Cronbach Alpha on a Yes/No scale

I'm attempting this and getting very low Alphas.

Is it advisable to use the measure with a 2 point scale?