Simkin and Roychowdhury's (2005) random-citation-copying model reproduces preferential attachment and sleeping beauties from the single assumption that most citations are copied

citation-copyingbibliometricspreferential-attachmentsleeping-beautiescitation-genealogy

In "A mathematical theory of citing," Simkin and Roychowdhury build a generative model of the citation graph on one behavioural premise: "a majority of scientific citations are copied from the lists of references used in other papers." An author picks a few recent papers, cites them, and copies some of the references those papers already carry. Under that single rule the model reproduces, without additional assumptions, two features observed in real citation data — the power-law distribution of citation counts normally attributed to preferential attachment — cumulative advantage, Price 1976; Barabási–Albert, the same rich-get-richer dynamic the vault tracks in bibliometrics as the Matthew effect — and "sleeping beauties," papers that go uncited for years and then are rediscovered. Copying, in this account, is the microscopic mechanism that produces the rich-get-richer statistics rather than an alternative to them: a reference already on many lists is more likely to be copied onto the next one. The authors report that the bare copying model must be augmented with a fitted per-paper "Darwinian fitness" parameter before it matches the empirical distributions closely.

This is the field-level companion to the paper-level method in claim-simkin-roychowdhury-2002-identical-citation-misprints-are-copy-fingerprints-implying-about-20-percent-of-citers-read-the-original, where the same authors used repeated identical misprints to infer that only about 20% of citers read the original. The 2002 paper measures copying on one much-cited paper; the 2005 paper asks what a whole graph built by copying looks like. The "copied object, not a record of contact" reading of a citation edge is what lets error-inheritance findings — GhostCite's paper-to-paper propagation, Ansari's paper-to-model inheritance — and graph-level statistics be seen as two faces of the same process.

Both Simkin–Roychowdhury papers count as one source for the single-source concentration cap (same author group): with the 2002 note, this is the second claim-note resting on that single author group, still under the cap of three. (Corrected 2026-09-27: this sentence originally called the 2005 paper an "unrefereed primary"; it was published refereed as JASIST 58(11):1661–1673, 2007, and the cited arXiv v3 is the accepted version. The same-author-group counting is unchanged.)