The recruiter explained that it was a 4-step process. First there was a 2-1/2 hour hackarank coding test. I passed that, though didn't at the time know that you can practice on the website to help prepare. Then there is a technical phone interview, which I passed. After that came a coding challenge, which had one exploratory data analysis problem and one machine learning problem. They were planning to change that section so it should be different now, but when I took it, but they had tricks such as giving you a link on the SSA website that points to corrupt data and see what you do with that. I did not pass that section unfortunately, and it was frustrating to have spent an entire weekend working on that project and have zero explanation why it did not pass. The fourth stage would have been an all-day in-person interview at their facilities.