Since the passage of PDUFA VI, there has been significantly increased interest in the use of real-world data and evidence (RWE) in the regulatory setting. In this talk, I present some examples of RWE use in CBER, such as BEST, SENTINEL, and post-marketing studies. I will also discuss issues that have arisen in these uses that can inform the current discussion. Topics covered include: How can we describe or quantify the strength of evidence provided by a study design? What is the role of existing studies in the literature that might be relevant? How can we mitigate the risk that a trial fails because of lack of power or other design problems that emerge during analysis? How can we handle the submission and use of extremely large data sets?