The Metrics Manifesto

CHAPTER 4Burndown Rates: Shifting Right the Bayesian Way

It is utterly implausible that a mathematical formula should make the future known to us, and those who think it can would once have believed in witchcraft.

— Jacob Bernoulli

The Art of Conjecturing. What a great title. Jacob Bernoulli is the author, and is also the guy striking a pose in our picture above. We add his book to our list of posthumously published statistical hits – right alongside Bayes’ theorem.

Bernoulli summarized The Art of Conjecturing as follows:

The art of measuring, as precisely as possible, probabilities of things, with the goal that we would be able always to choose or follow in our judgments and actions that course, which will have been determined to be better, more satisfactory, safer or more advantageous.¹

Sounds like security to me.

Bernoulli sought broader, more scientific uses for probability, as opposed to the gambling focus the theory had in his day. Gambling has constraints. For example, a die has six sides. A deck has 52 cards. You can count up all the ways (combinatorics) different outcomes can show up. Conversely, natural phenomena tend to be unbounded and squishy – yet still contain countable events. This goes for security as well.

Based on observation, you can count up how many people are born with one eye color versus others, and can start to make inferences about broader populations ...