Response shift in patient‑reported outcomes: definition, theory, and a revised model
Author(s) of the publication: Antoine Vanier, Frans J Oort, Leah McClimans, Nikki Ow, Bernice G Gulek, Jan R Böhnke, Mirjam Sprangers, Véronique Sébille, Nancy Mayo, the Response Shift - in Sync Working Group
This work is part of an international initiative: the Response Shift - in Sync Working Group.
Purpose The extant response shift definitions and theoretical response shift models, while helpful, also introduce predicaments
and theoretical debates continue. To address these predicaments and stimulate empirical research, we propose a more
specific formal definition of response shift and a revised theoretical model.
Methods This work is an international collaborative effort and involved a critical assessment of the literature.
Results Three main predicaments were identified. First, the formal definitions of response shift need further specification
and clarification. Second, previous models were focused on explaining change in the construct intended to be measured
rather than explaining the construct at multiple time points and neglected the importance of using at least two time points
to investigate response shift. Third, extant models do not explicitly distinguish the measure from the construct. Here we
define response shift as an effect occurring whenever observed change (e.g., change in patient-reported outcome measures
(PROM) scores) is not fully explained by target change (i.e., change in the construct intended to be measured). The revised
model distinguishes the measure (e.g., PROM) from the underlying target construct (e.g., quality of life) at two time points.
The major plausible paths are delineated, and the underlying assumptions of this model are explicated.
Conclusion It is our hope that this refined definition and model are useful in the further development of response shift theory.
The model with its explicit list of assumptions and hypothesized relationships lends itself for critical, empirical examination.
Future studies are needed to empirically test the assumptions and hypothesized relationships.
Response Shift, Theory
Quality of Life Resarch