During the past few decades, health status has become increasingly important in the clinical research of chronic obstructive pulmonary disease. The use of health-status questionnaires in routine practice can enhance understanding about the impact of the disease on the patient, improve standardisation and increase compliance through increased patient satisfaction. However, before health-status measurement in individual patients can be used in routine practice, questionnaires have to be validated on an individual level. In this article, the authors suggest a new method of assessing this individual validity, to enhance the use of health-status instruments in daily clinical practice, and thus improve treatment in chronic obstructive pulmonary disease.