Extended Data Fig. 9: Diseconomies of scale in combinatorial novelty. | Nature

Extended Data Fig. 9: Diseconomies of scale in combinatorial novelty.

From: Large teams develop and small teams disrupt science and technology

Extended Data Fig. 9

a, b, Changes in journal-based combinatorial novelty with team size from WOS articles. We calculate the pairwise combinational novelty of journals in the references of an article using a previously published novelty measure28. This novelty measure is computed as the tenth percentile value of z-scores for the likelihood that reference sources combine, so a lower value of this index indicates higher novelty28. Here we convert this measure to percentiles and subtract from 100 to improve readability, such that a higher score indicates greater novelty. It seems natural that a larger team would provide access to a wider span of literature. We find that novelty does increase with team size, but with diminishing marginal increases to novelty with each additional team member. Beyond a team size of ten, novelty decreases sharply (a). The probability of observing papers within the top 5% of the novelty distribution increases, and then decreases, with team size. The dotted line shows the null model that the probability of high novelty is invariant to team size (b). c, d, Calculation of combinatoral novelty in a different way. We select 241,648 papers published in American Physical Society Journals, 1990–2010, and analyse the probability of two-way (pairwise) and three-way combinations of the ‘Physics and Astronomy Classification Scheme’ codes using the Jaccard index. Similar to the novelty measure used in a and b, in the Jaccard index a lower value indicates higher novelty; we therefore convert it into percentiles and subtract from 100 such that a higher score indicates greater novelty. Again, we observe diminishing marginal increases to novelty with the growth of team size. e, f, We select 8,232,630 PubMed papers from between 1990 and 2010 and analyse the probability of two-way and three-way combinations of medical subject headings using Jaccard indices. The diminishing marginal increases to novelty effect are also observed in this context.

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