(From HBR Blog Network) -- The population used to be shaped like a pyramid: lots of young people, a medium number of middle aged, and a few old folks. But the demographic geometry has changed radically in just the last few decades in many parts of the world — and will shift further over the decades ahead in still others. We now have diamond- or rectangular-shaped populations in many countries and will at some point have inverted pyramids — the old will outnumber the young.
The United Nations' most recent study on demographic trends confirms these changes and puts to rest any assumption that the pyramid-shape will return. The former ratio of old-to-young already no longer exists in many countries and, much of the world will soon follow. Yet many of our talent management practices today are derived from this old idea.