The traditional path is the application, first Skype round, then an onsite visit broken into three parts: behavioral, case study, and final "fit" test with a higher up. I actually had around eight rounds under abnormal hiring circumstances, but I will highlight the tips and tricks for all the normal stages.
1) First Skype round: think about your past positions and find something you liked and something you didn't like about each one. Make sure that you have a logical flow to your life story. How did you end up here? How will AlphaSights help you continue on that path? My interviewer was pretty intense and would absolutely not take any skirting-the-question type answers. Honestly I thought that was pretty refreshing though, it gave me confidence in the company.
2) Onsite: the case studies. Prepare, prepare, prepare. I would recommend doing two case studies at home and seeing which one you prefer. This way you will have your system down for exactly how you find the right information and the right people. We discussed my case study for around a half hour and then the second phase began. You will be given a laptop and 15 minutes to complete two out of four prompts, not dissimilar to the case study you've already presented. I thought this was going to be the hardest part, but I work very well under pressure and the stress actually helped me succeed. My interviewers grilled me a little on my first answer, but had no reaction to my second answer (which I was very content with). The whole interview lasted about 2.5 hours. Advice: understand the company and what they do clearly before you start. When you have time to ask questions **have your interviewers go over every single step of the work flow process with you and know it by heart**
3) The final round with a Managing Director. My final round lasted three hours, and was the most detailed interview of my life. I found out the hard way that I didn't clearly understand a few details of the work process, but I was able to save myself. We later dissected every aspect of my childhood and life leading up to that moment and how it fit into working at AlphaSights. My interviewer seemed very tired and worn down, but he's a founding partner of a global firm and a relatively new father - I can hardly blame the guy. Overall it was a good experience.
Now, as I said, my interview process lasted unusually long. This is pretty much guaranteed not to happen to you, but because of this abnormal duration I acquired more information that most. After several supplemental rounds of interviews, reading every review on Glassdoor, and personally calling both present and past employees, here is what I've deduced: if you are a competitive, analytical people-person with good sales skills you will succeed at AlphaSights. The offices are astounding, the employees are great, just keep in mind this is a sales-heavy, quota-driven position. Some things during my interview process gave me an uneasy feeling about my future with the company so I declined my offer. However, that's my own reasoning over issues that really only specifically affect me. AS is working to hire the right people and give them the right support; they're staffed with some of the smartest people I've ever met and I have faith in them.
Good luck!