Chapter 15The typical scale that measures life- satisfaction runs from 0
(“not at all satisfied”) to 10 (“extremely satisfied”), and at a
stretch one could interpret 0 as equivalent to zero happiness.
But are all years of life after birth equally important? For
example is it twice as valuable if we save the life of a new-
born infant as if we save the life of a 40- year- old? Any other
assumption is bound to be controversial.
Finally there is the issue of the numbers born. Is the
world better if more people are born? For most practical
purposes we can take the number of births as exogenous.
But some policies clearly do affect the number of births,
and some countries like France, India, China, and Japan
have all tried to influence the fertility of their populations
either up (France) or down (the others). How do we evalu-
ate such policies? We can imagine two extreme positions.
One position says the only thing that counts is the propor-
tional distribution of QALYs among all those who are born
and that the number of people born is immaterial. Thus a
world of one million people is as good as one of seven bil-
lion who are equally happy and live equally long. The oppo-
site position says that what matters are total QALYs, added
up over all the people born.^16 According to that position we
should prefer a trebling of births even if it halved the QALYs
per person born. Probably most people would prefer policy
evaluation that focused on the proportional distribution of
well- being, and that is what we recommend.
Some Examples
This is not the place for detailed appraisal of policies to im-
prove well- being. But we can mention just a few examples.