But at least the significant difference between left and right hand remains.
It is common for them to be different; that’s why the survey asks for each hand separately. Inter-rater reliability (given the same scan) for this measurement is in the r=.9 range, if I remember correctly, so don’t feel that bad about it being variable; the underlying quantity is actually difficult to measure (but meaningful nonetheless).
the underlying quantity is actually difficult to measure (but meaningful nonetheless).
I don’t doubt that the measure is meaningful. The influence is surely real. The question is rather whether anything meaningful can be derived on the individual level.
It is common for them to be different; that’s why the survey asks for each hand separately. Inter-rater reliability (given the same scan) for this measurement is in the r=.9 range, if I remember correctly, so don’t feel that bad about it being variable; the underlying quantity is actually difficult to measure (but meaningful nonetheless).
I don’t doubt that the measure is meaningful. The influence is surely real. The question is rather whether anything meaningful can be derived on the individual level.