Hi all,
I have a longitudinal dataset that I'd like to calculate test-retest reliability for. However, I am not sure whether to calculate this for the cross-sectionally processed data or longitudinal data? It would seem to make sense to use the cross-sectional data, as the time points are independent, but then it means that the test-retest results would not be applicable in a dataset processed longitudinally. On the other hand, calculating reliability metrics for data processed in the exact same way as will be used in further studies seems to make sense also, but would calculating test-retest on the longitudinally processed data bias the results, as the data points are not fully independent?
Does anyone have any idea of the best way forward?
Thanks,
A