I did it with "reliability index". Is this the same as Cronbach's alpha??? It does not say so; so I thought mayber it was based on something else. So, it is the same! Another question is that: I have a questionnaire that measures perceptions and deals with several domains, adherence, control, severity, etc. I should not put all the variables into it and then hit "reliability index". Should I choose one domain with related variables at a time? Because I get a really low index when I put all, but when I put a domain at a time, I get a high index.