  The average age at which U.S. researchers get their first grant from NIH has
increased from 34.3 in 1970, to 41.7 in 2004. These data raise the crucial
question of the effects of aging on the scientific creativity and productivity
of researchers. Those who worry about the aging of scientists usually believe
that the younger they are the more creative and productive they will be. Using
a large population of 13,680 university professors in Quebec, we show that,
while scientific productivity rises sharply between 28 and 40, it increases at
a slower pace between 41 and 50 and stabilizes afterward until retirement for
the most active researchers. The average scientific impact per paper decreases
linearly until 50-55 years old, but the average number of papers in highly
cited journals and among highly cited papers rises continuously until
retirement. Our results clearly show for the first time the natural history of
the scientific productivity of scientists over their entire career and bring to
light the fact that researchers over 55 still contribute significantly to the
scientific community by producing high impact papers.
