In the basic machines, the compliance data monitors the patients usage only. In the upgrade machines, Elite & Pro models, the clinical data monitors the patients breathing rate, snoring index, apnea, hypopnea, and central apnea index, average pressure used, and breathing trends, plus compliance date. When you visit your doctor and he requires a download of your data, you will need clinical data to assist the physician in assessing your progress and making necessary changes to your treatment. If you do not have clinical data for an upcoming doctors appointment. You will need to loan one of our machines, with a $200 deposit for a minimum of 2 weeks to provide minimal clinical data for your doctors report.