As Dr. Simon mentioned in his lecture there are different types of clinical studies. This includes prospective clinical study which is collecting data in real time or retrospective which is using old data to be analyzed. As well as, a blinded study which may differ between single, double, and triple blind. Lastly there are randomized studies to prevent any bias, and placebos to compare patients who are using the real drug/device. My question is, based on your experience at your workplace have you observed any of the different types of studies and how was the study executed?