Rhetorical evolution in mathematical modelling: A diachronic analysis of metadiscourse in MCM/ICM contest papers

Abstract

This study investigates diachronic changes in metadiscourse within a relatively under-researched STEM genre: Mathematical Contest in Modelling (MCM) and Interdisciplinary Contest in Modelling (ICM) reports. Focusing on introduction sections, where writers must frame the problem, justify modelling choices, and persuade judges of the significance of their approach, we examine how student writers adapt rhetorical strategies in response to evolving evaluative demands. A corpus of 120 award-winning papers across two timeframes (2004–2013 and 2014–2023) was analysed using Hyland’s (2005a) model of interactive and interactional metadiscourse. Corpus searches were supplemented with functional coding to capture genre-specific forms. Results show a notable rise in engagement markers and boosters, accompanied by a decline in hedges and attitude markers. These trends indicate a shift toward more reader-oriented and assertive discourse, reflecting both broader developments in STEM communication and the contests’ particular communicative demands, where informative exposition is combined with persuasive promotion. The findings highlight the distinctive rhetorical identity of MCM/ICM introductions, which differ from other sections such as conclusions, and from conventional STEM writing more broadly. By tracing rhetorical evolution across two decades, the study demonstrates how student writers negotiate credibility, coherence, and persuasion within highly competitive contexts. The study contributes to ESP research by clarifying how genre- and section-specific pressures shape metadiscourse use. Pedagogically, it underscores the value of explicit instruction in the persuasive deployment of metadiscourse resources, helping STEM students develop rhetorical awareness alongside technical competence.