I somehow skipped through life up to now without encountering Benford’s Law. Now that I have, I am flabbergasted that it is not more widely known, or maybe I’ve just been hanging with wrong crowd. Here’s a hint. If I have a set of measurements, like the population of countries, or a list of atomic weights, how often would you expect the first digit of the measurement to be 1? Well, it can’t start with a zero, but any of the other 9 digits is possible, right? If you think the answer is 1/9, think again. The wikipedia post, MathWorld, and this DataGenetics blog posting are good starting points to understand why. It turns out this is useful in many areas of data analysis.