Both in clinical practice and in medical research, instruments are used to determine whether a patient improves or deteriorates. These instruments are called outcome measures. These instruments can consist of measurements, for example strength or sensation, or questionnaires informing about symptoms or quality of life. These outcome measures are used to evaluate how the patient is doing, for example if there is improvement after a certain treatment.

The discipline that focuses on the quality of measurements in clinical practice and medical research is called clinimetrics.