A creatinine clearance test measures how well creatinine is removed from your blood by your kidneys. This test gives better information than a blood creatinine test on how well your kidneys are working. The test is done on both a blood sample and on a sample of urine collected over 24 hours.
Therefore, 5 mg of oxycodone is about 16 mg of hydrocodone so oxycodone is about 3 times stronger than hydrocodone. However, geminigirl is right in that everyone is different. I have read that some say hydrocodone works better for their pain than percocet and viceversa. For me, percocet works a lot better for my pain.
Oxycodone, on the other hand, is considered to be more potent than the former because it is about 5 times more effective in pain suppression. Therefore, oxycodone is given to patients suffering from more severe pain like those related to trauma, chronic pain injuries and even cancer-related pains.