Productivity growth in developed countries has been slowing down, threatening to cause a long-term stagnation in living standards. One contributing factor could be that it is getting more expensive to find new scientific and technological ideas.

Economists Nicholas Bloom, Charles I. Jones, John Van Reenen and Michael Webb recently tried to measure innovation in various fields, and found that more and more researchers were needed to produce the same pace of discovery. That is an ominous trend.