“…Response shift theory in quality of life (QOL) posits that these changes are catalyzed by changes in health states, as well as other health-related events, treatment interventions, the vicarious experience of such events, and other events hypothesized to have an impact upon QOL (life events) [1,3]. Response shift has now been studied and recognized to affect adaptation to a wide degree of health conditions, including multiple sclerosis [4][5][6][7], cancer [8][9][10][11][12][13][14][15][16][17][18][19][20][21], stroke [22][23][24], diabetes [25,26], geriatrics [27][28][29], palliative care [30][31][32][33], dental disorders [34], and, most recently, orthopedics [35]. A meta-analysis done on response shift reported that response shift findings ranged from moderate to small effect sizes [36]; thus, adjusting for response shift in the data analytic phase of a clinical study can boost effect sizes from moderate to large [17].…”