Dangerous Numbers

STATISTICS NEVER LIE BUT LIARS ALWAYS USE STATISTICS

Numbers have a certain mystique: They seem precise, exact, sometimes even beyond doubt. But outside the field of pure mathematics, this reputation rarely is deserved. And when it comes to the coronavirus epidemic, buying into that can be downright dangerous.

Naturally, everyone wants to know how deadly COVID-19, the disease caused by the new coronavirus, is. The technical term for that is the case fatality rate — which is, put simply, the number of people who have died from the disease (D) divided by the total number of people who were infected with it (I), or D/I. As of Tuesday morning, at least 1,873 people were thought to have died from the disease worldwide and 72,869 people to have been infected.

But those figures may not mean what you think.