[R] estimate the reliability of a scale with dichotomous items

[William Revelle]

At 11:02 PM +0200 6/14/09, Martin Batholdy wrote:
>hi,
>
>How can I compute a reliability score of a scale consisting only of 
>dichotomous items?


RSiteSearch("cronbach's alpha") suggests the ltm,  psych, psy, 
psycho, epicalc, packages (among others).

There are a number of ways of estimating reliability, alpha is the 
most common (and perhaps overused).  Other ways include MacDonald's 
omega_h and omega_t as well as the six estimates of Guttman.  I tend 
to use the various functions found in psych, but then again, I am 
probably biased.

Bill



>
>
>
>thanks for any help!
>
>______________________________________________
>R-help at r-project.org mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.


-- 
William Revelle		http://personality-project.org/revelle.html
Professor			http://personality-project.org/personality.html
Department of Psychology             http://www.wcas.northwestern.edu/psych/
Northwestern University	http://www.northwestern.edu/
Attend  ISSID/ARP:2009               http://issid.org/issid.2009/