The challenge of comparability in sustainability reporting within the emerging standard-setting architecture

Purpose This paper aims to explain why standardisation does not necessarily produce substantive comparability in sustainability reporting and examines how the increasing concentration of standard-setting authority around institutions rooted in financial reporting may affect the conditions under which comparability enhances reporting quality. Design/methodology/approach This conceptual paper integrates insights from the accounting and sustainability reporting literature with a comparative documentary analysis of selected major reporting frameworks and guidance. It examines how comparability is conceptualised and operationalised across different reporting traditions and relates these approaches to the distinctive informational and measurement characteristics of sustainability reporting. Findings Sustainability reporting’s greater informational extensiveness and weaker calculative infrastructure amplify the risk that standardisation produces comparability in form without comparability in meaning. Institutional concentration is not inherently problematic, but concentration around institutions rooted in financial reporting may increase the salience of uniformity-oriented regulatory logics. Their translation is not deterministic; when reproduced without sufficient recalibration, however, they may suppress material contextual differences and weaken relevance and faithful representation. Practical implications The proposed framework helps standard setters calibrate common requirements across disclosure topics by identifying when standardisation supports substantive comparability and when it must be complemented by contextual or entity-specific information. Originality/value The paper reconceptualises comparability as a condition-dependent attribute of sustainability reporting quality. It argues that ex post comparability is endogenous to the ex ante representational choices through which information is selected, delimited and measured and develops five conditions – boundary equivalence, construct equivalence, contextual interpretability, measurement equivalence and temporal articulation – for assessing substantive comparability.