This appears to be exactly what they're doing. Here's an exchange on HN a couple of years ago on a similar question: https://news.ycombinator.com/item?id=5668

This appears to be exactly what they're doing. Here's an exchange on HN a couple of years ago on a similar question: https://news.ycombinator.com/item?id=5668324 https://news.ycombinator.com/item?id=5668324 In that submission, astronomers including Mike Brown of Caltech, Steve Vogt of UCSC, and Sara Seager of MIT all make assertions about typical exoplanet composition. A HN reader asked about the biased sampling issue. You can bet they are not just ignoring the possibility of biased sampling.