Lumpiness

Lumpiness is a term that's often used by Robin Hanson to describe things like innovation, secrets, AI progress, citations.

The general idea is something like, if something is "lumpy" then there are a few things that really matter, rather than a bunch of small things that add up.

"Lumpy: Nope, the CEO isn’t talking about poorly cooked oatmeal whenever he or she says revenues or orders were lumpy. This term means that sales were uneven during the quarter, with some weeks having low order rates and others having high order rates. The key is finding out why sales were lumpy and whether lumpy sales are normal for the company." [1]

"Operating revenues and expenses can be smooth or lumpy. A smooth revenue or expense is evenly and reliably spaced out over time. Smooth revenues include interest earned on investments and perhaps fee income, while smooth expenses include wages, rent, insurance, utilities, and so on. In contrast a lumpy revenue or expense is not evenly spaced out over time. Lumpy revenues include government grants and large donations while lumpy expenses include property taxes. If one were to classify all non-profit revenues and expenses as smooth or lumpy one would quickly find that most revenues are lumpy while most expenses are smooth." [2]

It's not clear to me how uneven a distribution must get before it gets calls "lumpy". For example, is a normal distribution lumpy, or must it be thick-tailed? is any non-uniform distribution lumpy? etc.