In the early 1960s, a prominent historian of science, Derek J. de Solla Price, examined the growth of science and the number of scientists over very long periods in history and summarized his findings in a book entitled Science Since Babylon (1961). Using a number of empirical measures (most over at least 300 years), Price found that science, and the number of scientists, tended to double about every 15 years, with measures of higher quality science and scientists tending to grow slower (doubling every 20 years) and measures of lower quality science and scientists tending to grow faster (every 10 years).
According to Price (1961), one implication of this long-term exponential growth is that "80 to 90% of all the scientists that ever lived are alive today." This insight follows from the likelihood that most of the scientists from the past 45 years (a period of three doublings) would still be alive. Price was interested in many implications of these growth patterns, but in particular, he was interested in the idea that this growth could not continue indefinitely and the number of scientists would reach "saturation." Price was concerned in 1961 that saturation had already begun.
How different are the growth rates in the number of
scientists and engineers in recent periods from what Price
estimated for past centuries? Table
Projections of employment growth are notoriously difficult to make, and the present economic environment makes them even more uncertain. Conceivably, the worldwide economic crisis will produce long-term changes in employment patterns and trends. The reader is cautioned that the assumptions underlying projections such as these, which rely on past empirical relationships, may no longer be valid.
The most recent BLS occupational projections, for
the period 2006–16, suggest that total employment in
occupations that NSF classifies as S&E will increase at
more than double the overall growth rate for all occupations
S&E occupations are projected to grow by 21.4%
between 2006 and 2016, while employment in all occupations
is projected to grow 10.4% over the same
Approximately 64% of BLS's projected increase in
S&E jobs is in computer and mathematical scientist occupations
BLS also projects that job openings in NSF-identified
S&E occupations over the 2006–16 period will
represent a greater proportion of current employment
than all other occupations—43.9% versus 33.7% (figure
The U.S. Patent and Trademark Office (USPTO) grants patents to inventions that are new, useful, and nonobvious. Thus, patenting is a limited but useful indicator of the inventive activity of scientists and engineers.
In its 2003 SESTAT surveys of the S&E workforce,
NSF asked scientists and engineers to report on their
recent patenting activities. Among those who had ever
worked, 2.6% reported that from fall 1998 to fall 2003,
they had been named as an inventor on a U.S. patent application (appendix table
By degree level, S&E doctorate holders have the highest
patent activity rate (15.7%), while bachelor's degree
holders in S&E-related fields have the lowest (0.7%)
USPTO does not grant all patent applications, and
not all granted patents produce useful commercial products
or processes. NSF estimates that in the 5-year period
for which data were collected, U.S. scientists and
engineers filed 1.8 million patent applications. USPTO
granted some 1.0 million (although applicants may have
applied for some of these at an earlier period). (See appendix table
Of those patents granted between 1998 and 2003, about 54% resulted in a commercialized product, process, or license during the same period. Scientists and engineers employed in the business/industry sector reported the highest commercialization success rate (58%), much higher than the education (43%) and government (13%) sectors. The overall commercialization rate varies by degree level, at 60%–65% for bachelor's and master's degree holders but 38% for doctorate holders (many of whom work in education, which has a low commercialization rate relative to other sectors).
Recent debates and legislative changes in many developed (and sometimes less developed) countries have focused on visa programs for temporary high-skilled workers. The United Kingdom and Japan are just two examples of countries that have made temporary high-skilled migration important parts of national economic policies.
A 1989 revision of Japanese immigration laws made it
easier for high-skilled workers to enter Japan with temporary
visas, which allow employment and residence for an
indefinite period (even though the same visa classes also
apply to work visits that may last for only a few months).
In 2005, 169,800 workers entered Japan in selected high-skilled
temporary visa categories, compared with just
over 30,000 in 1990 (figure
The United Kingdom's programs for the entry of high-skilled workers continue to evolve in ways to encourage migration and are currently part of an overall point system. Under the United Kingdom's recent Highly Skilled Migrant Program, admissions grew from 1,197 in 2002 to 21,939 in 2006. An important note for these numbers is that high-skilled EU citizens enter the UK without needing this visa, so actual high-skilled migration to the UK is likely to be much larger. During these years, the number of U.S. citizens entering the UK as high-skilled migrants grew from 273 to a still modest 629 (Salt 2007).