At group meeting, Chang Hoon Hahn, MJ Vakili, Kilian Walsh, and I had a discussion of the inference of variance: The idea is that there is an extremely dumb toy problem in the inference of a variance of a one-dimensional distribution of points that is directly analogous to the inferences of the two-point correlation function of galaxies in the Universe. I can show, with my toy problem, that conventional cosmological practice is wrong or biased. We got super-confused about terminology (variance of the variance, and the data or the estimator based on the data, and so on), which illustrates how hard this is going to be to write up!

In the afternoon I had my weekly tea with Phil Marshall (by videophone). We talked about the reproducibility crisis in the social and health sciences and how that might apply or be related to issues in astronomy. My view is that astronomy results fail to reproduce just like these other studies, but we don't notice it as much because we have stronger p-value requirements. But still subsequent studies tend to be inconsistent with previous studies. We discussed blinding and hypothesis registration; many astronomers are dead-set against these tools. We discussed why that is, and whether being against these is effectively being for irreproducibility.