Do star scientists erect barriers to entry for newcomers in their fields? Pierre Azoulay and Joshua Graff Zivin bring some data to the question raised in that famous quip from physicist Max Planck on how scientific progress really happens.

In 2003, the two of us made a wager. We had just left a talk by a renowned scientist, when Pierre quipped, “It must be amazing to work in his orbit, where his brilliance and the intellectual exchange of ideas must raise the level of scholarship of everyone around him.” Josh, a bit more sardonic in nature, replied, “I don’t know. I bet he consumes a lot of scarce research resources and commands an oversized amount of attention. He might well suck all the oxygen out of the room.” Without missing a beat, Pierre countered that this was really an empirical question. Nearly a decade-and-a-half later, we have some answers. It seems we were both right.

Together with Cristian Fons-Rosen, we have an updated working paper (NBER Working Paper 21788) that tackles this question head on. In particular, we explore the famous quip by physicist Max Planck that science advances one funeral at a time. While the father of quantum mechanics with full tongue in cheek may not have been thinking of his observation in economic terms, at its heart it is a claim about barriers to entry, albeit to a more loosely organized enterprise than the typical industry.

To probe this question, we exploit a very detailed employer-employee dataset from the academic life sciences, which we have painstakingly assembled over the years since our initial bet. Within this dataset we identify 12,935 elite scientists using criteria such as the amount of research funding received, publication citations, number of patents, membership in prestigious organizations, and career awards and prizes. Among those elite scientists, we focus on the 452 who died prematurely—before retiring or becoming administrators—to examine the impacts of that loss on succession and entry into the fields that they have departed.

Key to our analyses is a topographical mapping of scientific subfields based on intellectual linkages between scientists and their publications, rather than collaboration or co-citation patterns. While some members of the same subfield are connected by the ‘social baggage’ of collaboration and citation, others are not. It is also possible to observe entrants into a subfield that were not active in the area at all before the star has passed. Thus we can distinguish between the impacts of a passing star on those within her field—both her collaborators as well as competitors—from those outside it.

These results paint a picture of scientific fields as scholarly guilds to which elite scientists can regulate access, providing them with outsized opportunities to shape the direction of scientific advance in that space.

Consistent with previous research, we find that the flow of articles by collaborators into affected fields decreases precipitously after the death of a star scientist. In contrast, we find that the flow of articles by non-collaborators increases by 8.6% on average. Surprisingly, this surge is not driven by a reshuffling of leadership within the field, but rather by new entrants that are drawn from outside it.

Interestingly, this increase in contributions by outsiders appears to tackle the mainstream questions within the field but by leveraging newer ideas that arise in other domains. This intellectual arbitrage is quite successful—the new articles represent substantial contributions, at least as measured by long-run citation impact. Together, these results paint a picture of scientific fields as scholarly guilds to which elite scientists can regulate access, providing them with outsized opportunities to shape the direction of scientific advance in that space. We then explore the mechanisms through which these would-be entrants were held back while the star was alive.

Few of the deceased scientists served as editors of academic journals or on committees overseeing the issuance of research grants, so we rule out the possibility that the deceased scientists used their influence to limit who could or could not enter their fields. Rather it appears that the prospect of challenging a luminary in the field serves as a deterrent for entry by outsiders.

After their passing, however, we find evidence for influence from beyond the grave, exercised through a tightly knit network of collaborators. The loss of an elite scientist central to the field appears to signal to those on the outside that the cost/benefit calculations on the avant-garde ideas they might bring to the table has changed, thus encouraging them to engage. But this occurs only when the topology of the field offers a less hostile landscape for the support and acceptance of “foreign” ideas, for instance when the star’s network of close collaborators is insufficiently robust to stave off threats from intellectual outsiders.

Once in control of the commanding heights of their fields, stars tend to hold on to their exalted position—and to the power that comes with it—a bit too long.

In the end, our results lend credence to Planck’s infamous quip. Once in control of the commanding heights of their fields, stars tend to hold on to their exalted position—and to the power that comes with it—a bit too long.

While eminent scientists restrict the entry of new ideas and scholars into a field, gatekeeping activities could have beneficial properties when the field is in its inception; it might allow cumulative progress through shared assumptions and methodologies, and the ability to control the intellectual evolution of a scientific domain might, in itself, be a prize that spurs much ex ante risk-taking. Consistent with that view, we also find that the entrants who boost activity into the subfields formerly occupied by the deceased star are disproportionately likely to be future stars. Therefore, the outsiders of today can often turn into the stars of tomorrow—the circle of scientific life!

Pierre Azoulay is professor at the Sloan School of Management at MIT and Research Associate of the National Bureau of Economic Research.

Joshua Graff Zivin is professor of economics at UC San Diego, where he holds faculty positions in the School of Global Policy & Strategy and the Department of Economics.

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