I applied online. The process took 3 weeks. I interviewed at Mercer (London, England) in Dec 2017
Interview
Online application form / CV / cover letter followed by HireVue video interview and assessment centre. 30 seconds to prepare for questions (listed below) and 3 minutes to answer. Assessment centre pretty standard - group problem solving and individual presentation followed by 1 to 1 interview.
Interview questions [4]
Question 1
Tell us about a time that you have worked in a team to solve a problem? What challenges did you face?