Disciplinary tribes and the discourse of mainstream media expert opinion articles: evidencing COVID-19 knowledge claims for a public audience

Much applied linguistic research has investigated how experts from different disciplines – different “disciplinary tribes” – present knowledge claims, drawing on taken-for-granted disciplinary ideologies and epistemologies. However, this research has mainly focused on specialist to specialist communication rather than specialist to non-specialist communication. This article aims to fill this gap by examining a corpus of mainstream media “expert opinion articles”, written by experts for members of the public, on the topic of the COVID-19 crisis and published in The Guardian and The New York Times. The corpus included articles by experts in Medical Science, Medical Practice, Science, Humanities and Social Sciences, Law, and Economics. Using corpus-based discourse analysis, we consider the effect of discipline on the way that experts present and evidence knowledge claims. We compare the kinds of experts, their content focus, and forms of evidentiality seen in verbal evidentials used in the articles. The analysis identifies four discourse strategies: (1) deriving knowledge from experience; (2) invoking the knowledge of the expert community; (3) invoking vernacular knowledge; and (4) raising claims in argument or critique. Differences in disciplinary epistemologies lead to systematic differences in presenting and evidencing knowledge claims, even in texts primarily intended for a wide public audience.