•Scenario development can be understood as a valuation practice by which ideas about the future are constructed.•Valuation practices are important for organizations and for fields.•Mechanisms by which valuation practices alter relations include commensuration, categorization, narrative, performativity.•By attending to valuation in scenario development, we can be reflexive about what is gained or lost through the process.•We illustrate this in a case for an international elevator and escalator company.•We edit the method drawing on insights from valuation literature, especially the role of narratives. Scenario development is a core component of foresight practitioners’ and long-term planners’ work. Practices play a critical role in shaping and reifying taken-for-granted structures and ideas, and as such deserve attention. In this paper, we conceptualize scenario building as a practice of valuation. Doing so calls attention to constructive elements and highlights the importance of studying the practice and the field, not only to derive best practices, but to understand how they work and to what potential consequences. We illustrate these ideas with a scenario development consulting project for an international infrastructure company in which we alter the method in three main places: scanning, interim scenario work and scenario development. We demonstrate how conscious attention to the practice can drive subtle shifts in practice and how a ‘valuation lens’ encourages reflexivity about the use of practices.