Abstract: The assessment of health related quality of life aims at an
evaluation of the patient's perspective with regard to the consequences of
a disease or to treatment outcome. Frequently, there is a focus on change over
time. The outcome of measurement may reflect real change, but, on the other
hand, may also be the consequence of cognitive changes such as changes in the
reference system of the patient or in values and concepts about health and
disease. Changes that are reflected in repeated measurements and that may not
be attributed to real change in quality of life, are defined as response
shifts. It is a challenge to separate change due to response shifts from those
due to real change. The present article reviews research on this field and
provides recommendations for future assessment procedures.
Keywords: Quality of life, response shift, overview