[DanBC]

The author is a mathematician, and thus used to thinking about percentages and numbers.

Gerd Gigerenzer has a nice book, Reckoning with Risk (or Calculated Risks: How to Know When Numbers Deceive You in the US), in which he calls for people to stop using percentages and to use natural numbers numbers instead.

When you say that someone's risk has increased by 33% they usually have no idea what that means, but they think it's scary. But if the risk used to be 0.001% then a 33% increase isn't much to worry about.

The book has many examples from real world medicine of people having great disruption caused because they took medical treatment based on a faulty understanding of the numbers. It wasn't just lay people making the mistakes either; many doctors and consultants were getting the numbers wrong.