The Drake equation is a lighthearted way of estimating the number of extraterrestrial civilisations that currently exist in the Milky Way galaxy, using probabilistic arguments such as the fraction of stars with planets, the probability a planet is suitable for supporting life, the probability a suitable planet does support life, the probability the resulting lifeforms are intelligent, and so on. Each of these individual probabilities has to be estimated, and for many of them there is considerable disagreement about their plausible range.

Estimates of the number N of extraterrestrial civilisations arising from the Drake equation range from N = 10−12 — which would suggest we are alone in the galaxy and possibly in the observable universe — to N = 15.6 million, which would suggest we most definitely are not.

Give a brief (and lighthearted) critique of the Drake equation as a statistical estimator, considering its precision and bias. Given what you know about its precision, is the concept of bias even relevant here?