Two independent Tier-1 sources each place a legitimation-type mechanism and the Matthew effect (or its formal twin, cumulative advantage) inside one framework of citation distortion, but neither uses the vault's exact two labels side by side

citation-biasmatthew-effectlegitimationpopularitysociology-of-sciencebibliometricscitation-theoryunverified-negative

A 2026-11-03 search for a source that explicitly names "citation bias" (the EBM lineage) and the Matthew effect (the bibliometric lineage) as two poles of one axis found nothing (observation-no-literature-located-crossreferences-citation-bias-and-matthew-effect-as-one-axis). A follow-up 2026-11-04 search of the adjacent citation-theory literature — reviews of why people cite, rather than reviews of citation-bias measurement specifically — located two sources that each place a legitimation/persuasion-type mechanism and the Matthew-effect/cumulative-advantage mechanism inside one shared framework, under some common label. The two do it with different degrees of symmetry, and the difference is the finding. Haustein, Bowman & Costas (2016) genuinely enumerate "persuasion hypothesis" and "Matthew effect" as two of four named, co-equal poles in one sentence of a citation-theory taxonomy of distortion. Bornmann & Leibel (2025) are asymmetric: an EBM-style outcome-favoring mechanism is their one highlighted example of citation bias, while cumulative advantage/preferential attachment appears in a separate section as a mechanism of non-independence that generates bias — inside the same framework, but as a cause rather than a co-equal instance.

Haustein et al. also supply, in the same paragraph as their Matthew-effect pole, the label equivalence that makes the two findings commensurable: Price (1976) "demonstrated the Matthew effect mathematically... and referred to it as cumulative advantage or success breeds success," and "[i]n network theory, the Matthew effect is referred to as preferential attachment." That is the same Price (1976) Bornmann & Leibel invoke while never once writing "Matthew effect." So the vocabulary gap between the two vault labels is bridged explicitly inside the outside literature — by one of these two sources, about the other's chosen term — rather than being a gap a reader has to close by inference.

No single located source writes the sentence "citation bias and the Matthew effect are two poles of one axis" using exactly those two names: "citation bias" occurs nowhere in the Haustein chapter, "Matthew effect" nowhere in Bornmann & Leibel, and neither paper cites Gøtzsche, Greenberg, or Duyx (all four negatives confirmed by exhaustive full-document reads, 2026-11-05 audit). [unverified -- could not confirm or deny after search] remains the fairest tag for the literal question as posed in question-does-an-outside-literature-name-the-legitimation-popularity-citation-distinction. But the broader claim — that some outside scholarship already treats legitimation-selection (content-fit to a predetermined conclusion) and popularity-selection (prior popularity, independent of content) as two named poles of one distinguishing axis — now has two independent, Tier-1, directly-read sources behind it, which the 2026-11-03 session did not have, with Haustein the stronger of the two on co-equal enumeration. The axis appears to live in the theory-overview layer of the literature (works assembling taxonomies of "why citations distort"), not in either empirical specialty's own papers.