I applied through an employee referral. The process took 6 months. I interviewed at Inter-American Development Bank in Apr 2016
Interview
It is a panel that will ask specific technical questions. You have to really be prepared, the interviewers are senior members of the bank. I would recommend trying to network and have someone to advocate for you before the interview. The bank is very political.
Interview questions [1]
Question 1
Why apply demand or offer type of instruments to foster innovation in countries of the region