Abstract: The widespread availability real-world study (RWS) offers valuable insights into disease treatment, disease management, and socio-economic status in routine practice, as well as cautionary tales and methodological challenges such as the discovery of sample heterogeneity and bias of data and its correction. This paper summarizes the common bias and its control in the process of design, implementation and analysis for RWS in order to promote the standardization and rationality of the implementation of RWS.

Key words: real world research, bias, selection bias, information bias, confounding