Missing-indicator method. The missing-indicator method was proposed for missing confounder data in etiologic research7, 8 and has since received much attention in the medical literature.3 – 6, 10, 12 ...

Qualitative research methods provide formal approaches to collect, analyse and present qualitative data in a rigorous way. This can generate hypotheses, make comparisons, or provide descriptive and ...

In data collection, we design the necessary parallel groups for intervention studies. We ensure the planned sample size is sufficient for the selected analysis methods and provides reliable assessment ...