This document provides background information to the profiles on quality of life in seven EU enlargement countries that are published as individual papers – Croatia, Iceland, Kosovo, Montenegro, Serbia, Turkey and the former Yugoslav Republic of Macedonia . It identifies the countries that participated in the survey, explains survey characteristics, and provides definitions of indicators reported in individual country papers. In 2011–2012, when the third European Quality of Life Survey (EQLS) was carried out, the European Union consisted of 27 Member States. It enlarged to 28 when Croatia joined on 1 July 2013. For individual country papers - see Related content.