The Tension Between Real World Data and Clinical Trial Data

The trend is to actually use more real world data. Patients that are not in the clinical trials, they're not in these narrow slices of the Olympic athletes of patients. And we can use these patients, for example, to simulate and to emulate what a control arm will look like. So my follow up question is kind of around like, what do you think are the barriers to using something like synthetic control arms today?