there will be 2 round of phone interview before coming to the on-site interview. The first one is only to confirm if you are interested in Groupon and the team. The recruiter from Seattle will call you to make an introduction about the team and the coming interview process. Then 2 days later it is said to have a technical test online according to the HR. However, the project manager only asking questions about statistical problem and project experience after the project manager introducing herself later. The questions are more about the statistics problem, rather than the technical questions I was supposed to have, that is why I failed finally. However, I have to say if you know what exactly about the team, you may prepare well.