Fig. 1

Data harmonization process. Reprinted with permission: Buffart LM, Kalter J, Chinapaw MJ, Heymans MW, Aaronson NK, Courneya KS, et al. Rationale and design for meta-analyses of individual patient data of randomized controlled trials that evaluate the effect of physical activity and psychosocial interventions on health-related quality of life in cancer survivors. Predicting OptimaL cAncer RehabIlitation and Supportive care (POLARIS): Systematic reviews. 2013;2:75