Multi-billion dollar space telescope programs arent only feats of aerospace engineering. They also feature lies, damn lies, and statistics. Or at least statistics. They definitely feature those, as does all good observational astronomy. The problem with statistics is, in order to get a clear definitive answer, you need lots of samples. And, to put it mildly, its hard to find lots of samples of planets with alien life on them. And even harder to prove that the signals we think are caused by alien life arent caused by some other non-biological process. Or at least thats the theory underpinning a new paper available in pre-print on arXiv from David Kipping of Columbia University (and Cool Worlds YouTube fame).