This paper considers the micro-econometric analysis of patients' hospital choice for elective medical procedures when their choice set is pre-selected by a general practitioner (GP). It proposes a two-stage choice model that encompasses both, patient and GP level optimization, and it discusses identification. The empirical analysis demonstrates biases and inconsistencies that arise when strategic pre-selection is not properly taken into account. We find that patients defer to GPs when assessing hospital quality and focus on tangible attributes, like hospital amenities; and that GPs, in turn, as patients'
agents present choice options based on quality, but as agents of health authorities also consider their financial implications.