Costs and Benefits

[james_davis_nicoll]

Suppose one was near a large, old country that was largely cut-off from external trade (using Canada as the norm) and suppose that various of their social traditions resulted in a somewhat decreased lifespan. If opening the country to trade might reasonably be expected to undermine the social patterns that lead to decreased lifespans, how does one calculate how many people in the large old country could suffer unrequested lifespan truncation without outweighing the total lifespan gained? Is it as simple as saying "They live on average 77.43 years. After being opened, they may live 79.96 years (to pick values out of the hat), an increase of one part in 30. Therefore as long as the shrinkage getting there is no more than one part in 30, this is a net gain for the people in the old, large country."