Exercise: Meibography continued, answer 1

Question 1: Why would a strong relationship between the gestalt scale and gland counting indicate good concurrent validity?

‘Concurrent validity’ means that the variables used in the validity assessment are recorded at the same time. As the gestalt assessment and the gland count are done on the same image of the eye, they are concurrent. It is not clear whether one of these measures is being used to validate the other, for example treating the count as an objective criterion to validate the gestalt assessment, or whether each is being used to validate the other without a criterion, which would be construct validity.

A statistic indicating the strength of the relationship, such as a rank correlation coefficient, would be more useful than a P value.


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