Is Facebook the future of the national census?

Every ten years, governments around the world conduct their national census: a count of the resident population.

This is no easy task.

The 2011 Chinese census, for instance, was a vast operation relying on six million enumerators taking census questionnaires from door to door.

Knowledge of a population’s composition is crucial for government planning, for example in terms of investing resources in elderly care.

In some countries, it is the basis for dividing parliamentary seats over electoral…