11/7流病研究方法論課堂學習

"Dynamic change of patient-reported outcome can be quantified by a cross-section study."

I thought we need to use a follow-up study design to get dynamic change of patient-reported outcome. However, if the onset (e.g., stroke patients) is different, we only need a cross-section study design to get this kind of information. Regarding sample size for conducting studies, we need 50 cases in random sampling, whereas we need 100 cases if patients are from a sample of convinience.