Science Is Becoming “Less Disruptive”

A new study by researchers at the University of Minnesota, published in Nature, suggests that science and technology are becoming less “disruptive”.

Innovation in science is slowing down

Despite “unprecedented expansion of scientific and technological knowledge”, the rate of innovation in science is slowing down, according to the paper. Associate Professor Russell Funk from the Carlson School of Management at the University of Minnesota led the study, alongside PhD student Michael Park and Professor Erin Leahey from the University of Arizona. The evidence for this slowing down the team put forward in the paper is as follows:

• Studies document declining research productivity in semiconductors, pharmaceuticals and other fields.
• Papers, patents and even grant applications have become less novel relative to prior work and less likely to connect disparate areas of knowledge, both of which are precursors of innovation.
• The gap between the year of discovery and the awarding of a Nobel Prize has also increased, suggesting that today’s contributions do not measure up to the past.

Exactly why this slowing down is occurring – and the true extent of it – is unclear, prompting the research team to analyze data from 45 million papers and 3.9 million patents across six decades (1945–2010) to search for answers.

A decline in disruptive science from 1945–2010

Funk and colleagues drew inspiration from foundational theories of scientific and technological change to characterize innovation. These theories propose two different types of “breakthroughs”: those that improve existing knowledge – and therefore “consolidate the status quo” – and those that disrupt existing knowledge, propelling subsequent research in novel directions.

To quantify these factors across the six decades, the researchers devised “the CD index”. “We looked at what happened to the prior work that was cited by a scientific paper after that paper was published. When citations to that prior work declined (and declined more dramatically) after the paper was published, we considered the paper to be more disruptive,” Funk explains.

The intuition here is that research following a highly disruptive paper is less likely to cite the original study on the basis that the research focus has been shifted in a different direction. The CD index ranged in values from -1 (least disruptive work) to 1 (most disruptive).

Tracking how the CD index changes over time, the researchers conclude that papers and patents are now less likely to be disruptive and are more likely to be consolidating. Disruptiveness has declined by 91.9% for the social sciences to 100% for the physical sciences. For patents, disruptiveness decline rates between 1980 and 2010 range from 78.7% for computers and communications to 91.5% for drugs and medical. Across both papers and patents, the rates of decline are greatest in the earlier decades and appear to begin to stabilize between 2000–2005.

Since 1980, the decline rate has been “more modest” in life sciences and biomedicine and physical sciences, and “most marked” in social sciences and technology. Across the board, the researchers suggest that recent papers and patents do less to “push science and technology in new directions”.

Accounting for changes in citation practices

The time period analyzed in the study – 1945 to 2010 – encompasses major technological changes in society, such as the introduction of the internet. The ability to access papers online surely could have impacted citation practices. Technology Networks asks Funk how the researchers controlled for varying practices. He says, “We used multiple different approaches to adjust for changing citation practices. The first was normalization. In essence, we created new versions of our CD index measure that adjusted for the average number of citations received by papers in each year of the study.”

The second was a regression-based approach. “We obtained values of the CD index for each paper after adjusting for many different factors, including the year of publication, measures of citation, publication and authorship practices,” Funk explains. The researchers also used a simulation approach, where they computed the CD index on citation networks that were similar to the real data in terms of the number of citations made per paper and year, age gaps between citing and cited paper, etc. “We then compared the values of the CD index on these simulated citation networks to those in the real data. Across all approaches, we continued to see a dramatic decline in disruptiveness,” says Funk.

The greatest challenge faced by the researchers was investigating and ruling out alternative explanations: “To do that, we collected data from many different databases on scientific publications (to ensure our results weren’t driven by a quirk of our data source). We also looked at alternative metrics, including natural language text, which took a lot of computational power to process,” he says. “We’re lucky, though, that there are a lot of great software and computational tools available today for doing this kind of research.”

Why is science less disruptive?

Funk and colleagues state their research “reinforces concerns about slowing innovative activity”. But why is this happening? The data suggest the decline in disruptiveness is unlikely to have been driven by citation practices, or the quality of work that has been published. Instead, it might reflect a general shift in the landscape of the scientific establishment. 

The burdens placed on a field that, in simplistic terms, endeavors to provide an unbiased approach for comprehending our world, continue to grow. Poor funding opportunities, limited career options, sluggish peer review processes and the dreaded “publish or perish” paradigm are just some of the issues frequently highlighted as barriers to innovation.

These challenges – among others – feature widely in the #SciTwitter community’s response to Funk and colleagues’ paper. It’s also argued that, historically, scientists in training would have pursued a level of expertise in one specific field. In modern times, early career researchers are expected to have a much broader understanding of the sciences, which might stifle innovation. After all, it’s challenging enough learning and retaining sufficient knowledge to “keep up”, never mind knowing enough to devise a radically new hypothesis.

Reading the discussions, you’ll likely notice an overarching theme suggesting the system is “broken”. Funk has noticed a similar theme but is reluctant to say in broad terms that this is the case. “It’s a somewhat amorphous claim and not something that we study directly in the paper,” he says. “But I do think that our results suggest the need to look more carefully at contemporary scientific institutions, and whether there are changes that can be made to better support research that pushes science in new and valuable directions.”

Is Funk hopeful that positive change is achievable? “Yes!” he says. “We are living in an era where more data is available than ever before on both how science is made and the products of scientific work, which will hopefully lead to more insights on how to best support innovation.”

What’s the solution? To promote disruptive science and technology, Funk and colleagues propose that scholars are encouraged to read widely and should be given time to keep up with the rapidly expanding knowledge frontier. “Universities may forgo the focus on quantity, and more strongly reward research quality, and perhaps more fully subsidize year-long sabbaticals,” they write. In addition, they suggest that federal agencies invest greater quantities of funding in “riskier” and “longer-term” individual awards that support careers, rather than specific projects.

The research team are hoping to conduct additional research that further unpacks the cause of declining disruptiveness and innovative activity in science and technology. “We have also been working to develop better and more nuanced measures of disruptiveness, particularly by using the growing availability of full text data from papers and patents,” Funk concludes.

Dr. Russell Funk was speaking to Molly Campbell, Senior Science Writer for Technology Networks.

Reference: Park M, Leahey E, Funk RJ. Papers and patents are becoming less disruptive over time. Nature. 2023;613(7942):138-144. doi: 10.1038/s41586-022-05543-x.