Re: question about measure creation statistics

Posted by Paul Oosterveld on Nov 18, 2011; 8:28am
URL: http://spssx-discussion.165.s1.nabble.com/question-about-measure-creation-statistics-tp5002888p5003728.html

Michael,

If you score the responses true/false the items are dichotomous. If not please
elaborate on the scoring rules of the items.

KR-21 is a special case of the reliability coefficient with the (general
unrealistic) assumption of equal item difficulties (means). Cronbach's alpha
and KR-20 are identical. The only distinction is that KR-20 is somewhat easier
to compute, something that was useful when calculation had to be done by hand.
It is perfectly valid to use the reliability command in SPSS to compute the
"alpha" on dichotomous variables and call it KR-20.

Paul

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