I have been searching for information on how to conduct internal reliability assessments but have been unsuccessful. Is there a book or website that can inform me on how to conduct these analysis? I have to measure the internal reliability on tasks that measure the response time of the participants.

Also, can I use the Cronbach's alpha in a task where the responses are open ended and are scored in 0, 1 and 2 depending on the accuracy of the answer? I was thinking about defining the values of the scores from 0-2 and treat it as an ordinal variables as one would in a questionnaire. Would that be acceptable?

Since you appear to be familiarised with psychometric tests, you may know that sometimes you are instructed to end the test after the child has failed a determined number of questions. Thus we end up with children who answered 30 questions and some who answered only 15, for example. When measurring the reliability of a task like the one I mentioned above where the child gets a determined point corresponding to the accuracy of his responses, do you score the asnwers he did not give as a 0 or just as an empty space? I am sorry if this is too basic.

  • $\begingroup$ Welcome to the site. There is no need to say "thanks" on any questions here. For better answers, you might want to discuss the specific applications you have in mind. $\endgroup$
    – AdamO
    Jun 30, 2016 at 18:51
  • $\begingroup$ the applications of measuring the internal reliability? My study uses a great variety of psychometric tasks and batteries and since I am comparing three groups, I want to make sure the batteries I used are internally reliable so that my comparisons are more trustworthy. I could rely only on p-values or the effect size but is that enough? I cannot compare test-retest nor inter-rater reliability as only one investigator was involved and one session. I hope this asnwered your question, if not I can add what is missing. $\endgroup$ Jun 30, 2016 at 19:01

1 Answer 1


Internal consistency (internal reliability) is a major topic in psychometrics in and of itself. Your best bet is a good psychometrics textbook. I recommend:

Thorndike, R. M., & Thorndike-Christ, T. (2010). Measurement and evaluation in psychology and education (8th ed.). Boston, MA: Pearson. ISBN 0-13-240397-8.

To answer your specific question about Cronbach's alpha, yes, it's applicable in that situation.


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