A modeller's fingerprint on hydrodynamic decision support modelling

Model results can have far-reaching societal implications, requiring fit-for-purpose models. However, model output is resulting from a particular path chosen with each modelling decision. We interviewed fourteen modellers in the Dutch water management sector in order to study how decision support hydrodynamic modellers make modelling decisions. An inductive-content analysis was performed. We identified eight motivation-categories. Individual and team considerations mostly motivate modelling decisions. We identified patterns between the motivation-categories and their occurrence across modelling steps. Modelling decisions during model implementation were found to be more in the modeller's direct sphere of influence, while decisions concerning model structure and data selection more outside of it. So, even though modellers can leave their fingerprint, their sphere of influence and thus their fingerprint's clarity is bound by institutionalised predefined decisions. Thus, models and their results are shaped within a broader sphere than the modeller's alone, requiring a broader consideration of organisations and standards.