Many governments strive to build and sustain a vibrant scientific culture, investing a significant part of their gross domestic product in research and development. Presumably their aim is to encourage scientific research that ultimately will benefit the state, the economy and society at large. They are also looking to create jobs. But there can be too much of a good thing.

Japan's bold initiative to produce 10,000 postdocs by 2000 was designed to create better science jobs and foster discovery. But it has run into a fairly big problem — there are now too many postdocs and not enough jobs (see page 1084). Back in 1995, the Japanese government recognized a need to increase the number of postdocs so that young investigators had more opportunities to conduct research on their own ideas, operating in a more independent fashion than had been the case previously. By 1999, a year earlier than projected, Japan had reached its target. By 2005, there were 15,000 postdocs, 61% of whom were in science and engineering. Permanent jobs in academia began to dry up.

US scientists, especially biomedical scientists, will be all too familiar with this chain of events. For years, US science associations and vocal members of the scientific community have recognized that there is a glut of postdocs and a shortage of entry-level academic jobs (see Nature 422, 354–355; 2003).

Although Japan and the United States have different cultures, there are common themes that could resolve their postdoc problems. A 2005 US National Academies report called Bridges to Independence suggested some solutions. Postdocs should get as much funding as possible for their own research, and there should be limits to the amount of time they spend under their respective principal investigators. Once that time is elapsed, they should become a different category of permanent employee.

Nations, it seems, face common challenges when adjusting their science workforces to maximize innovation, discovery and sustainable research opportunities for talented scientists.