The whole process has taken nearly four weeks from July to August. The first round is technical test for some basic statistic and machine learning knowledge, 10 question during 30 minutes. The second round is HR interview about your background and motivation. The third round is a telephone interview during 45 minutes with 2 data scientists, we have discussed my project and a business case in Booking.com. Last round is on-site interview, 4 hours and 3 interviews. In fact, except the second interview, the others were really nice. During the second interview, I met two "data scientists", one of them is not real data scientist but more business. He was very rude and interrupted me and his colleague many many times. And the question from him was really strange (build a machine learning model without any history data), and during the exchange with him, I find he didn't understand some basic concepts in data science domain. The other people I had met were pretty nice except him. Booking said they have 140 data scientists, but after the discussion with them, I found part of them is BI (I have no prejudice for BI), they analyse the data and make the decision, which is not correspond to my understanding for Data Scientist