We present a simulation study to increase the throughput at an Endoscopy center. The center has the capacity to process up to 80 patients a day. However, they were only processing about 50 patients/day, on average. We have built a simulation model to better understand the causes of this low throughput and to determine the worthiness of some proposed changes the �������� � ������� � ����������� � ��������� � � �� � �xamined a fraction of a factorial design of seven factors at two or three levels each. Results helped determine that two perceived causes for the formation of bottlenecks actually did not have much impact, whereas the policy to assign rooms, which was never suspected, has a lot to do with it. We were also able to understand that a major part of the problem is rooted in customers arriving too early for their procedures. We also have identified new venues for future research.