One important ethical aspect of the use of models for decision making is the relative power of the various actors involved in decision support: the modelers, the clients, the users, and those affected by the model. Each has a different stake in the design of decision support models, and the outcome of modeling depends on both the technical attributes of the model and the relationships among the relevant actors. Increasing the transparency of the model can significantly improve these relationships. Here, we explore the importance of transparency in the design and use of decision support models.