Overall, it was a very negative interview experience.
1st round is a short data set assignment after online application.
2nd round is with HR discussing your background, achievement, and feedback from current/previous managers.
3rd round is a data challenge which you have to complete within 7 days. The data challenge is pretty complicated and took significant amount of time to complete. After you submit the report, there are 3 rounds of follow up/bonus questions, each one takes a good amount of time to complete.
4th round is an onsite interview, meeting VP of product, a research analyst, 2 engineers, and the founder. Mostly behavior questions, and a small case.
The whole interview experience shows that the company doesn't have a basic respect for the interviewees. For example, one of my interviewers had chewing gum in this month during the onsite interview. And when I found out that I didn't get the job, I asked the HR to approach the hiring manager for feedback on the onsite interviews, so I can learn and apply it to my future interviews. But I got a very generic response (something like 'we think other candidates are better fit for the role'), which I was surprised, since the candidates put a great amount of time and effort into the interview process, but they weren't willing to spend 5-10min sharing feedback for the candidates. I have never had situation like this before with any other companies I interviewed. It looks like 'no interview feedback' was at least mentioned by 3 interviewees on Glassdoor from 2016 to 2018, and HR commented in 2017 that they were working on improving this. But so far by the time I interviewed no real improvement was made.
Furthermore, the interviewers presented themselves to be very arrogant. There were a lot of frowning when I answered the questions, and they appeared to be very impatient when I was a little bit stuck at the case question. And for the behavioral questions part, they were more reading off from their checklist, instead of getting to know you and about your experience. Another thing I found weird about their work culture was when someone made a mistake, they Venmo money to the party that was affected with the message 'sorry my mistake made you spend more time working on XXX'. I understand they wanted to acknowledge mistake but the transferring money part I found very weird.
Lastly, they advertised themselves having a culture focusing on impact, but when I asked them about in what ways they measure the impact, they couldn't give me a clear answer but instead was saying that that was the challenges they were facing.
So think twice before you begin the interview process and make sure you are interested in what they do and the culture of the company.