Funding for this research was provided by:
EuroQol Research Foundation (EQ Project 2016620)
Text and Data Mining valid from 2018-02-22
First Online: 22 February 2018
Compliance with Ethical Standards
: This work was funded by the EuroQol Research Foundation (Grant number EQ Project 2016620).
: All authors (Mathieu F. Janssen, Gouke J. Bonsel and Nan Luo) are members of the EuroQol Group.
: All data analysed in this study are stored at the central data archive of the EuroQol Research Foundation. The data are available from the EuroQol Research Foundation upon reasonable request.