I need to perform a computation of reliability of a 5-point Likert scale having 6 items. From a factor analysis I found that my scale is a multidimensional scale (3 factors), so I cannot use Cronbach's alpha to compute reliability. I have seen in several papers that it is possible to use the multidimensional extension of the McDonald's omega. Does the omega function in the psych package allow to do this?

Also, is there an R function to compute the Stratified alpha?

  • $\begingroup$ It would help if you answered the questions I asked for your preceding question... (and please register your account so that you could vote and accept @Jeromy's earlier answer.) $\endgroup$
    – chl
    Jun 10, 2011 at 8:56
  • $\begingroup$ it seems you are asking 2 not related questions, please ask separately. Also if you leave unanswered clarifications asked in your previous questions, people will hesitate in answering your new questions. $\endgroup$
    – mpiktas
    Jun 10, 2011 at 9:24

1 Answer 1


First yes it does, see http://www.personality-project.org/r/psych/help/omega.html and second there is a package sirt http://www.inside-r.org/packages/cran/sirt/docs/stratified.cronbach.alpha that you can use for stratified alpha.


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