Making Purpose Verifiable

The global rise of sustainability disclosure requirements has intensified demands for external verification of non-financial information. Yet sustainability commitments particularly those articulated as corporate purpose -often resist conventional audit approaches. This paper investigates how auditability is constructed when the object of verification is normative, evolving, and contested. Drawing on the French Société à mission as an empirical setting, we examine the relational dynamics through which verification practitioners (Organismes Tiers Indépendants, OTIs) and auditees organisations jointly produce what counts as verifiable. Through qualitative research combining focus groups with mission committee chairs, corporate executives, and OTIs, as well as in-depth interviews conducted over a five-year period (2021-2025), we identify four archetypal modes of constructing auditability: metrification, proceduralization, narrative coherence, and deliberation. We show that these modes are not mutually exclusive but combine and hybridize in practice, reflecting ongoing negotiations between verification providers and organizations. Our findings contribute to the sustainability assurance literature by theorizing auditability as an interactional accomplishment rather than a technical precondition, and to the purpose-driven organization literature by revealing how verification processes may either reduce purpose commitments to instrumental compliance or preserve their trajectory integrity. We discuss implications for the design of verification frameworks amid regulatory expansion and political contestation of sustainability initiatives.