"I knew who I was this morning, but I've changed a few times since then": A study combining register and self-reported QoL data in assessing how response shift may occur in an injury population.

Aims: The phenomenon of response shift may occur when people are exposed to a traumatic event and reevaluate the meaning of important aspects of their lives; a phenomenon that a traditional pre- and post-assessment cannot catch. Hence, the aim of the study was to increase the knowledge of how response shift may occur in people who have suffered an injury.

Methods: The current study is a register-based cohort study including 2512 participants. Data were retrieved from the Swedish LifeGene project and an online questionnaire, including the EQ5D. In order to analyze how response shift may occur, a "Then-test" and Structural Equation Model (SEM) were used.

Results: The results showed a clear indication of response shift through recalibration. The SEM analysis confirmed that participants significantly shifted their response between the post- and retrospective measurements. Significant differences were found for the VAS and for two of the five EQ5D dimensions: anxiety/depression and pain.

Conclusion: This study provides additional knowledge to how response shift can occur in an injury population. This information can guide the next generation of QoL measures and be used as guidance for designing interventions for those suffering injuries. Furthermore, it may have an impact on how to interpret evaluations of interventions.