The quality of living ranking, which takes into account the political, social, economic and socio-cultural and natural environments as well as education, public services, housing, recreation and consumer goods, is topped by Vienna, followed by Zurich and Auckland, Munich and Vancouver.
Geneva was eighth, Bern tenth, and Baghdad came last.
Mercer compares every year living in New York with the life in 221 other cities to help companies and organisations determine a fair salary for employees on international assignments.
Packages need to include an adequate hardship allowance, which compensate expatriates for decreased quality of living between home and host location, Mercer said.
“Factors such as political stability, crime levels and the quality of medical facilities have the largest weighting because they have the largest impact on daily life expatriates may encounter on an international assignment,” Slagin Parakatil, a senior researcher at Mercer, told swissinfo.ch.