On Benfords Law

Posted on Aug 12, 2020

Today I Learnt about Benfords Law.

Benford’s Law states that numbers follow a certain distribution curve based on their first digit.

So if you have some sufficiently large set of numbers, and took just the first digit of each number, you would expect to see about 30% of those first digits to be 1s, about 17% 2s and so on.

Graph illustrating Benfords Law

Benford’s distribution by gknor

This remains true whether the dataset is population of US cities, distances between galaxies or voting patterns in elections.

Because of the nature of this law you can use it to determine non-natural number distributions - for example evidence tampering with data sets. If you have a set of numbers that you would expect to follow Benford’s Law, and it does not, that can suggest that those numbers have been artificially tampered with.