Each person will have his or her own standard of improvement. For example, one patient may want and need to be able to lift a coffee pot and pour coffee without spilling. Another patient may say that getting a good night's sleep is what counts.

A meaningful change from the patient's point-of-view may not be the same as what society or the physician would say. Society might see the patient's ability to go back to work sooner as the important change. The physician may say there were no complications and that's what counts.

Researchers often use patient surveys of questions before and after treatment to calculate the minimal clinically important difference (MCID). The MCID is a measure of success and guides treatment. If the MCID shows a benefit from treatment, then it's possible no further treatment is needed. If not, then further treatment may be needed. The patient and doctor decide this together.