Humanitarian medical organizations rely on information on and from the ground to evaluate their effectiveness and accountability. Related digitalization efforts within health information systems assume an instrumental rationality in the use of data.However, previous research identified a multitude of factors influencing actual information use for evidence-based decision-making for healthcare delivery. This case study, anchored by critical realism philosophy, unpacks these nuances against the backdrop of a globally operating organization (Médecins Sans Frontières). It aims to highlight the contextual conditions and structures that enact the contingent mechanisms at work in project monitoring within humanitarian health management information systems. By applying an affordance-based causal analysis, three mechanisms are identified: first, an analytics service provides templated analysis modalities resulting in user-producer-provider relationships; second, the rationalization and synchronization of content and software artifacts gives rise to the standardization strategy of flexible generification; third, the study uncovers the potential for increased internal social discourse and advocacy through collaborative and mobile data analysis. This paper proposes that mechanism-based explanations can be useful for theory-building in information systems research as well as for providing insights to practitioners in the humanitarian health sector.critical realism, health management information systems, humanitarian organizations Armed conflicts, epidemics, natural disasters and other humanitarian crises are inherently complex, protracted situations that lead to large numbers of refugees, internally displaced and entrapped persons. In these situations, humanitarian short-term emergency responses often evolve into long-term interventions (Spiegel, 2017;Vila-Pozo & Sahay, 2018). Organizations providing aid in these complex contexts are expected to demonstrate their effectiveness and accountability to the donors and the recipients of aid. The organization's information system (IS) is a critical tool in fulfilling this demand (Lewis & Madon, 2004;Read et al., 2016), as information and communication technologies (ICTs), when embedded in a broader view of technological, social and institutional innovations, are considered a catalyst for improved health outcomes (Walsham, 2020).David Huser: The current affiliation is with BAO Systems, Washington DC as an independent contractor.