In addition to an exact definition, correct measurement of any patient-relevant value is important. Assessing the value of medical interventions is mainly made difficult by the uncertain interpretation of a study's end points, among others caused by the use of invalid surrogate parameters, the clinically unreasonable combination of end points or the arbitrary POST HOC combination of end points as well as the premature termination of studies because of unclear evidence of superiority. As numerous errors can be made when measuring patient-relevant end points, it is the task of the Institute for Quality and Cost-Effectiveness in Health Care not only to describe patient-relevant value in general (and particular for different cases), but also to point out measurement errors in this regard, so that they can be avoided in future.