The concept of the data structure is part of the accepted and relatively unexplored background of the information disciplines. As such, the data structure is treated largely as a technological artefact, helping to support but somewhat isolated from considerations of institutional order. This paper develops an alternative consideration of the data structure which focuses upon the constitutive capacity of such artefacts within institutional order. This viewpoint builds upon literature from the language/action tradition, the more recent work of John Searle on social ontology as well as the small amount of work which proposes the actability of data structures. To help provide some grip on the slippery notion of institutional order we consider it here in terms of the notion of business patterns. The term business pattern is used to refer to a coherent and repeating sequence of action involving humans, machines (including IT systems) and other artefacts (such as data structures) appropriate to some way of organising. The paper also describes a way of visualising either existing business patterns or envisaged business patterns through the pattern ‘language’ of pattern comics. We ground our approach using material gathered within a research study of a key routine enacted within a large manufacturing organisation. Within this routine a mismatch was experienced between what the data structures within the production IT system was telling production managers and what was experienced on the ground by production operators. We show how an actability worldview of data structures expressed in terms of business patterns offers a fruitful way of making sense of problem situations such as this. It also suggests important ways of thinking differently about the nature of design in relation to data structures. “Until I know this sure uncertainty, I'll entertain the offered fallacy.” William Shakespeare, The Comedy of Errors 
Instituting facts: Data structures and institutional order