This paper advocates something I would call a triple blind, keeping the doctor, the patient, and the statistician who analyzes the data in the dark as to which treatment group is which. This avoids problems where the people analyzing the data will either consciously or subconsciously manipulate the data to get a preferred result. Interesting idea, though it represents an awful amount of work to pull it off.
Robert MacCoun, Saul Perlmutter. Blind analysis: Hide results to seek the truth. Nature 2015 (October 7), 526(7572), 187-189. Available at http://www.nature.com/news/blind-analysis-hide-results-to-seek-the-truth-1.18510.