I believe that if a clinical study is to occur the study should occur as a double blind study. Any bias that could alter the outcome of the study should be avoided at all cost. It is normal to want to trust the researchers or doctors to not tell the patient who is trial and who is control but their is still room for human error. A simple slip up of a patients classification can ruin that patients statistical relevance to the whole study. A double blind study stops this from occurring. If the researcher or doctor is not able to tell the patient what they are receiving there is less room for error to occur.