A posting abroad is often seen as a stepping stone to greater things. But the question for employers is whether all it does is give valuable workers a leg up with a rival.
The 11th annual Global Relocation Trends Survey by relocation company GMAC and the National Foreign Trade Council has found expatriate employees are much more likely to leave their jobs, either during or after an international assignment, than general employees.
Retaining expatriate talent was a considerable challenge for companies, it added.
Attrition rates among expatriate employees were at least double the rate of non-expatriate employees.
Among general employees, the attrition rate was 10 per cent, this rose to 21 per cent for expatriate employees who left in the midst of an international assignment and 23 per cent who left within a year of returning home.
When asked to identify the top reasons for refusing an international assignment, family concerns were the key worry, followed by a spouse's career.
Other key factors leading to an assignment failure were partner dissatisfaction, family concerns, inability to adapt and poor job performance.
But opportunities for international assignments were also on the rise.
After a steady decline since the 1998, now 47 per cent of companies reported an increase in the size of their current expatriate population last year, compared with 31 per cent in 2004, which had been an all-time survey low.
More than half – 54 per cent – anticipated additional growth in the coming year, against 38 per cent last year.
For the second year running, the U.S retained its status as one of the world's most challenging countries for international assignments, behind China and India, primarily because of greater delays in the immigration process, visa issues and security concerns.
The world's expatriate workforce is also becoming increasingly female, the survey found.