Last night I gave a guest lecture to a third year nutrition class at the University of Ottawa. The students are in the program to become dietitians and my role was to talk to them a bit about nutrition issues in low income countries.

As part of the lecture I showed them the following slide, which explains why malnutrition is important (because it is responsible for one-third to one-half of all child deaths).

But these data are about 10 years old. At the time I made the slide over 11 million children died per year. I told them that the data are old and these numbers are no longer accurate and I asked what they thought the current rate was. And the comments were mostly variations on “I don’t know, but it is definitely higher”. This surprised me. I didn’t expect them to know the right answer, but I thought they would know that the death rate was decreasing.

Then I remembered a TED talk I recently watched by Hans and Ola Rosling. They showed that most people get these sorts of questions wrong most of the time. So they developed four rules of thumb that you can apply when confronted with these sorts of questions.

1. Most things improve.

2. Most people are in the middle (most distributions are unimodal (a one-humped camel, not a two-humped camel).

3.Social and health progress can precede economic progress, but the majority already have most “things” (education, electricity etc).

4.Assume you will exaggerate the problem.

The rules don’t apply all the time to all things, but they are generally helpful.

The Beatles had it right and it is getting better all the time.

(By the way, the right answer is that currently about 6 million children die every year).