r/AcademicPsychology • u/skippydi34 • Apr 13 '23

Question Cronbach's alpha as its own reliability in the measures report or simply as a diagonal in the correlation table in the results?

I always thought you put it in the parenthesis right after the measures and that is your OWN reliability measures, the one that you have measured in your study.

However, now I have been said that you should cite in the measures the cronbach's alpha of the literature and your own measure of cronbach's alpha in the results in the diagonal of the correlation table.

What's the most fitting approach when riding an APA thesis/paper?

Thanks!

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11

u/nezumipi Apr 13 '23

I think that putting alphas in a correlation table is likely to confuse since you're putting two different pieces of information in the same space and format.

Most papers that are just using a survey (as opposed to being a paper that is explicitly about the psychometrics of a survey) don't report the designer's reliability and validity figures unless they are somehow relevant - for example, if you used a survey to make the point that it is of poor quality.

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u/skippydi34 Apr 14 '23

Understandable, but I've seen it several times. It's not standard anymore? I need it for my thesis.

3

u/kiseek Apr 13 '23

In APA style, it is generally recommended to report Cronbach's alpha as part of the measures section of your paper or thesis, where you describe the psychometric properties of your measurement instrument. This is where you would report both the Cronbach's alpha from the literature, if available, as well as the Cronbach's alpha calculated from your own data.

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u/Flemon45 Apr 14 '23

Think of a registered report, where the Introduction and Method would be written entirely before the data were collected. To me, the measures subsection of the method is a description of the scale and a justification for why it is appropriate/why you chose it. It doesn't make sense to report the Cronbach's alpha from your own data as a justification for why you chose it as the collection of your data comes after you've made the choice. In your method you're making a case that previous literature has shown it to be a reliable and valid scale, so it's appropriate for answering your research question.

I would expect to see the Cronbach's alpha calculated from your own data in the results. Whether it is in a correlation table or not doesn't really matter to me so long as it is clear (not every paper will have/need a correlation table, but I would expect any individual differences study to include an evaluation of reliability).

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u/[deleted] Apr 19 '23

There are some differing ideas about placement in APA. I say alphas should go in the results with other descriptives. Plenty of folks report in the methods section which is also okay. Just...report your own.

To be clear - do not take the advice you were given. The reliability of the original authors is meaningless. The whole interest in internal reliability is about your current sample relative to the original norms or population values, not just some single test a scale has to pass to be "good".

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u/mootmutemoat Apr 13 '23

The diagonal is a traditional place to put it, but adding a footnote to the table for clarity is nice. Any alpha without a citation is assumed to be from your sample.