randomized controlled trial (RCT) has been regarded as the gold standard for evaluating the effect of intervention because it can avoid various biases that may occur in the design and implementation of clinical trials and has many advantages. However, the whole research process of RCT has high requirements, strict control, and great difficulty, and there is a certain gap with actual clinical practice. It is impossible to infer the risks and benefits in the presence of complications and concomitant treatment. The observational efficacy comparison study presented by the U.S. Health Care Research and Quality Administration can be used to systematically study the real-world effects of different interventions, prevention and treatment strategies, etc. for prevention, diagnosis, treatment and monitoring of health conditions, and can be used as a useful supplement to RCT.