[Study] Allocation concealment [Burke et al18] Unclear [Feighner and Overo19] Unclear [Frank et al20] Unclear [Lepola et al22] Unclear [Mendels et al23] Unclear [Montgomery et al24] Unclear [Stahl25] Unclear [Gastpar et al21] 
Unclear
L o w
U n c l e a r
H i g h