[tmoertel]

Interestingly, recent research suggest that you can make better decisions by combining experimental and observational data than by using either alone:

https://ftp.cs.ucla.edu/pub/stat_ser/r513.pdf

> Abstract: Personalized decision making targets the behavior of a specific individual, while population-based decision making concerns a sub-population resembling that individual. This paper clarifies the distinction between the two and explains why the former leads to more informed decisions. We further show that by combining experimental and observational studies we can obtain valuable information about individual behavior and, consequently, improve decisions over those obtained from experimental studies alone.