Over the years, some words have established themselves at the London Mathematical Laboratory as a useful vocabulary. “Laplacing something” and “Weltschmerz” (p.32) are among these words. Another is “Democratic Domestic Product” or DDP — a humorous term, like all the others, that reflects the first response a student trained in ergodicity economics will have when confronted with Gross Domestic Product (GDP).
When statistical things go wrong, it’s often because someone unknowingly assumed ergodicity where that wasn’t ok. This can have dramatic effects in everyday language: I will use the example of incarceration rates. I will then present a visual illustration to discuss the role of time scales.