title: Patient bias, investigator bias and the double-masked procedure in clinical trials.
mesh_terms: D002986:Clinical Trials as Topic; D006801:Humans; D007600:Judgment; D010470:Perceptual Masking; D010919:Placebos; D011287:Prejudice; D012106:Research; D012107:Research Design
chemical_list: D010919:Placebos