Doctors need to understand the benefits of new treatments from patients’ perspectives, because they must judge the relative risks and benefits of offering such treatments to patients. The field of health status assessment has evolved to meet this need, and several patient completed instruments have been developed that are valid, reliable, and sensitive to treatment.1 Such tools can provide invaluable insights into how a treatment affects outcomes such as function and quality of life, which can be more important to patients than survival.2 3 4 For some conditions, however, measures of disease specific health status are not available, and global assessments of clinical change are used.

Although valid approaches are available for measuring global change experienced by patients,5 6 simple ad hoc measures are often used and can be assessed from the perspective of the patient or the doctor. In the accompanying survey of trials included in systematic reviews, Evangelou and colleagues determine whether patients …