After the shortlisting the first thing that happens is the online assessment - which has two main parts- numerical and logical assessment and personality assessment. I considered both of them as relatively simple.
The first telephonic interview was with my line manager and colleague. It had the generic questions like - why this role, why now, tell us about you, explain an executed project which was data intensive etc. I had a 30 min discussion.
Finally if you get through all this - there is the Personality assessment which is the tough one. The general conversion is 3 candidates per open position. Our PA has three parts - interview (with HR and senior management), business case presentation and role play. Personally the most difficult was the business case presentation where extensive amount of scattered info had to be presented concisely and clearly. The case wasnt given as a preread and there was one hour of preparation before the presentation. There was no group discussion for this role.
If you pass or not, you get very honest and detailed feedback about your assessment which is really insightful.