In the US raising children is an art hotly debated. Experts directly contradict each other. Kids need liver; they should never eat liver. Infants should sleep alone; they should sleep with others; they should be stimulated constantly; they should be left alone to cry. Strong opinions rally support and sell more parenting books. It’s hard for parents, already fearful for the safety of their children, to make sense of all the advice.

It’s hard also to assess risks in the modern world. A family might forbid their little girl from playing at a friend’s house where the owners keep a gun, but let her play at a house with a swimming pool. The girl’s chances of dying in the pool, however, are nearly 100 times greater than her odds of being killed by the gun. We underestimate risks we can control, like driving a car or keeping a kitchen clean, and overestimate risks we cannot control, like flying in an airliner or buying food prepared by others. Planes, though, are very safe, and kitchens aren’t.

People also overestimate risks from things that cause dread. Terrorists and mad cow disease are dreadful but much less likely to kill than simple heart disease from bad eating habits.