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OP said that Africans _die young_, not that the _young die_. Lowering the life expectancy lowers the average age if it's because the older don't live long.

• thaumasiotes 8y ago
  But a pattern of dying young is not evidence that older people don't live long. Dying raises the average age if you die below the average age, and lowers the average age if you die above the average age. Thus, a 16-year-old dying can only lower the average age if the average age was already less than 16. A four-month-old dying can only lower the average age if the average age was already less than 4 months. (Which, obviously, it can't be.) Dying lowers life expectancy regardless of when you do it, and it has a stronger lowering effect the earlier you do it. The dying four-month-old has a really strong negative effect on life expectancy, but a strong "positive" effect on the average age. They're orthogonal[1] concerns. [1] OK, not technically orthogonal. One will help predict the other, especially if you know the average age. But the point remains that a negative effect on life expectancy can be associated with any effect at all on the average age, because all effects of death on life expectancy are negative.
  • _carl_jung 8y ago
    That's a good comprehensive description and I agree.