achievement” in a statistical framework using data covering more than a century. His sample is of Nobel prize winners in physics, chemistry, medicine, and economics (N = 544) and great technological inventors (N = 286). Figure 6-1 shows the age distribution for each group from his sample. In each case, the average age was 39.1 There is considerable dispersion in the distribution.
Another important finding of Jones’s study is that the average age at which invention occurred increased over the twentieth century. For recipients of Nobel prizes in physics, chemistry, and medicine, the increase in the median age has been around 2 years per century, while the increase in the mean has been 8 years. The increase has resulted from an increase in the starting age (the age at which the youngest inventors did their prize-winning work) as well as the ending age (the age at which oldest inventors did their prize-winning work). In part, the increase in the ending age is due to the longer life span over which invention occurs that comes from longer life expectancy.
From a policy perspective, one of the most important findings is a delay in the start of the creative period. Jones finds a significant delay in the onset of scientific creativity. He points to two potential factors in the delay: the increased complexity of acquiring knowledge because of the greater depth of accumulated knowledge and the longer time to a final degree (see also National Research Council, 1990 and 1998).
There is genuine concern on the part of the scientific establishment in universities as well as federal scientific agencies that the longer time for young researchers to enter their careers as productive scientists is due to institutional impediments.
Patents and Other Areas
Another measure of innovative output, and one that is generally closer to economic activity, is patents. Patents have been the subject of study as indicators of inventive output for many years (see the overview in Griliches, 1990). They have the advantage of passing some threshold of importance and nonobviousness. Their shortcoming is that they have highly variable importance and commercial value. Jones (2009) examined the characteristics of patent awardees over the twentieth century and found increases in three important measures: (1) the age at which an inventor makes the first invention; (2) a measure of specialization in patents; and (3) the size of teams. He concludes that the nature of the scientific and inventive process is becoming more complicated as more knowledge is accumulated. Additionally, the age at which applied knowledge was crystallized in the form
1Age refers to the age at which a discovery was made, as best as could be determined.