tion, and this within-organization collaboration decreases the diffusion of discoveries to other scientists. Incumbent firms are slow to develop ties with the discovering university stars, leading some stars to found new biotechnology firms to commercialize their discoveries. Star bioscientists centrally determined when and where NBEs began to use biotechnology commercially and which NBEs were most successful. Stars that span the university-NBE boundary both contribute significantly to the performance of the NBE and also gain significantly in citations to their own scientific work done in collaboration with NBE scientists. Nations differentially gain or lose stars during the basic science- and industry-building period, indicating the competitive success of different national infrastructures supporting development of both the basic science and its commercial applications.

Ideas in People

There are great differences in the probability that any particular individual scientist will produce an innovation that offers significant benefits, sufficient possibly to outweigh the costs of implementing it. We know that a wide range of action differs between great scientists—including our stars—and ordinary scientists, from mentoring fewer and brighter students to much higher levels of personal productivity as measured by number of articles published, number of citations to those articles, and number of patents (5, 7, 8).

As shown in Table 1, among the 207 stars who have ever published in the United States, we observe higher average annual citation rates to genetic-sequence-reporting articles, a scientific productivity measure, for stars with greater commercial involvement: most involved are those ever listing a NBE as one’s affiliation (“affiliated stars”), next are those ever coauthoring with one or more scientists then listing a local NBE as their affiliation (“local linked stars”), and then those listing only such coauthorship with NBE scientists outside their local area (“other linked stars” who are less likely to be working directly in the lab with the NBE scientists).d We distinguish local from other on the basis of the 183 functional economic areas making up the United States (called BEA areas). In addition, being listed as discoverer on a genetic sequence patent implies greater commercial involvement. For the U.S. as a whole, stars affiliated with firms and with patented discoveries are cited over 9 times as frequently as their pure academic peers with no patents or commercial ties. The differences in total citations reflects both differences in the quantity of articles and their quality as measured by citation rate, where quality accounts for most of the variation in total citations across these groups of scientists.

Why Intellectual Human Capital? In most economic treatments, the information in a discovery is a public good freely available to those who incur the costs of seeking it out, and thus scientific discoveries have only fleeting value unless formal intellectual-property-rights mechanisms effectively prevent use of the information by unlicensed parties—i.e., absent patents, trade secrets, or actual secrecy—the value of a discovery erodes quickly as the information diffuses.

We have a different view. Scientific discoveries vary in the degree to which others can be excluded from making use of them. Inherent in the discovery itself is the degree of “natural excludability”: if the techniques for replication involve much tacit knowledge and complexity and are not widely known prior to the discovery—as with the 1973 Cohen-Boyer discovery (9) —then any scientist wishing to build on the new knowledge must first acquire hands-on experience. High-value

Table 1. U.S. stars’ average annual citations by commercial ties and patenting


Stars by gene-sequence patents

Type of star


Some patents

All stars

NBE affiliated*




Local linked




Other linked




Never tied to NBE§




All stars




The values are the total number of citations in the Science Citation Index for the 3 years 1982, 1987, and 1992 for all genetic-sequence discovery articles (up to April 1990) in GenBank (release 65.0, Sept. 1990) authored or coauthored by each of the stars in the cell divided by 3 (years) times the number of stars in the cell.

*All stars ever affiliated with a U.S. NBE.

Any other star ever coauthoring with scientists from NBE in same BEA area (functional economic area as defined by the U.S. Bureau of Economic Analysis).

Any other star ever coauthoring with scientists from NBE outside the BEA area.

§All remaining stars who ever published in the United States.

discoveries with such a high degree of natural excludability, so that the knowledge must be viewed as embodied in particular scientists’ “intellectual human capital,” will yield supranormal labor income for scientists who embody the knowledge until the discovery has sufficiently diffused to eliminate the quasi-rents in excess of the normal returns on the cost of acquiring the knowledge as a routine part of a scientist’s human capital.e

Thus, we argue that the geographic distribution of a new science-based industry can importantly derive from the geographic distribution of the intellectual human capital embodying the breakthrough discovery upon which it is based. This occurs when the discovery—especially an “invention of a method of discovery” (10) —is sufficiently costly to transfer due to its complexity or tacitness (1115) so that the information can effectively be used only by employing those scientists in whom it is embodied.

Scientific Collaborations. Except for initial discoverers, the techniques of recombinant DNA were generally learned by working in laboratories where they were used, and thus diffusion proceeded slowly, with only about a quarter of the 207 U.S. stars and less than an eighth of the 4004 U.S. collaborators in our sample ever publishing any genetic-sequence discoveries by the end of 1979. In a variety of other disciplines, scientists use institutional structure and organizational boundaries to generate sufficient trust among participants in a collaboration to permit sharing of ideas, models, data, and material of substantial scientific and/or commercial value with the expectation that any use by others will be fairly acknowledged and compensated to the contributing scientists (16).

Zucker et al (1) relate the collaboration network structure in biotechnology to the value of the information in the underlying research project: the more valuable the information, the more likely the collaboration is confined to a single organization. As expected, diffusion slows as the share of within-organization collaborations increases, so organizational boundaries do operate to protect valuable information effectively. In work underway, we get similar results in Japan: the value of information being produced increases the probability that collaborators come from the same organization.


Related results, reported under “Star Scientist Success and Ties to NBEs” below, demonstrate that these differences reflect primarily increased quality of work (measured by citations per article) while the star is affiliated or linked to a NBE.


In the limit, where the discovery can be easily incorporated into the human capital of any competent scientist, the discoverer(s) cannot earn any personal returns—as opposed to returns to intellectual property such as patents or trade secrets. In the case of biotechnology, it may be empirically difficult to separate intellectual capital from the conceptually distinct value of cell cultures created and controlled by a scientist who used his or her nonpublic information to create the cell culture.

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