This type of screening is relatively recent, so I've never seen it when I was at ATK.
Knowing the firm and given the time frame, I guess this a very level filter to make sure :
- you communicate in a clear way
- you are motivated by the job and the firm
- you have what it takes to move to the next step
So if you have prepared for case interviews, no doubt you'll be ready for this.
Sorry for not being able to be more specific, but I hope this will help.