The original meaning of “allocation concealment” is that the statistician and the trial designer who generated the random sequence and allocation sequence should not recruit and allocate the participants for the purpose of avoiding selection bias. In the process of generating allocation sequence, combined blinding measures are so called “setting blinding”, for instance, by using “double simulation”. We use a example to describe how to perform an adequate allocation and conceal the sequence, and setting blinding. Another example is used to describe how to report the methods of randomization, allocation concealment and the effect of blinding, etc.
Blinding is an effective measure to control and reduce the bias caused by the subjective factors of participants in a study. However, the failure of blinding results in more bias. Therefore, it is necessary to assess blinding quality in clinical trials involving blinding. The relevant international articles and methods of blinding assessment were summarized in this study. According to the present situation of blinding assessment, researchers don't pay enough attention to the assessment of blinding quality, relevant studies lack, comprehensive methods and tools for blinding quality, and researchers have discrepancy with time points in blinding quality. Therefore, it is necessary to conduct further studies in all aspects, and it is suggested that comprehensive blinding quality scales should be developed according to the key influencing factors of the implementation of blinding. Through the assessment of the implementation of key factors, the risk and degree of blinding should be confirmed in order to better interpret and assess researcher results.