Blinding study was introduced to avoid bias in the evaluation of treatment effects. As you have mentioned, double blinding studies require blinding patient, who is unaware of which treatment is given and also blinding the investigator. Thus, it guarantee objective judgement of efficacy and safety outcomes. By doing blind study, symptoms and subjective outcomes are not influenced by knowledge of treatment assignment. This improves the reliability of clinical research results. There are may advantages of double blind because the results are shown accurate however there are disadvantages as well. More often, Double blind study is limited in pharmaceutical industry. Such as lack of adequate demographic controls when study is being done, predictability of the drug’s identity and recruitment size. In order for drug to be approved, double blind studies are the standards by FDA. It requires two double blind study showing the drug is superior to placebo and at least equal to a standard other competing drug which indicated the certain condition for which the drug is being test.