Science in the 1990s and into the early 21st century continued to advance the frontiers of knowledge—but less efficiently than it did earlier in the 20th century, according to a new study commissioned by the National Science Foundation (NSF). The report examines scientific publication trends in the top 200 U.S. academic research and development institutions from 1988 to 2001. Whereas funding and other research inputs rose dramatically, the yield of published research papers fell. Quantifying this decline [graph], the report concludes: "It can be calculated that the same resources that produced 100 publications in 2001 would have produced 129 publications in 1990."

The report, "U.S. Academic Scientific Publishing," published November 19, follows a July 2007 NSF study which found that the absolute number of science and engineering (S&E) articles published by U.S.-based authors in the world's major peer-reviewed journals plateaued in the early 1990s even as funding and personnel increased. In response, a news analysis, "U.S. Output Flattens, and NSF Wonders Why," published in Science later in 2007 examined various hypotheses but failed to resolve the mystery.

The new NSF report confirms the 1990s inflection point: "[T]he evidence suggests that the growth trend either slowed or stopped altogether at that time." Significantly, the report cautions that the plateau "should not be confused with a decades-long and familiar decline in the U.S. share of the world's S&E articles." In other words, the waning productivity in the U.S. is not explained by the (inevitably) more rapid growth elsewhere in the world.

The new report advances some possible explanations: increased complexity of research, more comprehensive articles, greater expense for journal submission and research expenditures rising faster than inflation. Collaborations, measured by the number of institutions involved in producing a given paper, are up, and might be imposing higher costs from increased communication. Biomedical research productivity perhaps has fallen because after receiving a large infusion of federal funding in the past decade it may take time for new or expanded research efforts to become efficient.

But again, no smoking gun emerges. Factoring in differences in the degree of collaboration had little impact on the productivity results. And increased resources were not redirected into, for example, greater patenting activity. "There is no convincing evidence that patents are substituting for publications," according to the report.

Something important and less than ideal is happening, however. Even as other nations gain ground, the U.S. remains the world leader in science. Within the U.S. scientific community academic research is essential to the health of the nation's research system. The recent publication trends put its vitality in question with potentially historic implications. As the NSF report noted: "The trends are worthy of attention because they indicate a marked shift from a historical pattern."

Spokespersons for the American Association for the Advancement of Science, National Institutes of Health, Howard Hughes Medical Institute and John Holdren, director of the White House Office of Science & Technology Policy, declined to comment on the report. The offices of U.S. Rep. Daniel Lipinski (D–Ill.), chair of the House Subcommittee on Research and Science Education, and Rep. Rush Holt (D–N.J.), a former physics professor, also turned down requests for comment. Calls to the Senate Commerce, Science and Transportation Committee were not returned.