Within the field of clinical trials, rating is the process by which a human evaluator subjectively judges the response of a patient to a medical treatment.
Furthermore, some clinical outcomes can only be assessed by the patient (a "private phenomenon").
[3] Because the evaluation is subjective, this can result in both inter-rater or intra-rater reliability.
[4] When conducting clinical trials, ensuring rating consistency is important, but can prove to be quite difficult to obtain.
Studies dealing with such indications as pain, mental disease or mood are not able to easily track progress with physical or physiological testing, rather, verbal subjective human testing is used.