Carbon Lighthouse Engineer Interview Questions
& Process

It started with a phone call and then went to an analytics test. I had trouble connecting with the interviewer, partly because they didn't seem to value my PhD. They asked me multiple times to change my answers to reflect experiences outside of graduate school, which was tough since most of my career has been in grad school. You'll need to generalize your graduate experiences so it's not obvious they were from grad school. The test involved an Excel spreadsheet with sample data and had a 1-hour time limit. I wasted time figuring out how to use Excel and dealing with its quirks. In hindsight, I didn't interpret the data correctly, and I wasn't invited for an in-person interview. I did appreciate that the process and the transitions between stages were quite fast.

I applied online and heard back about two weeks later via email to schedule a phone interview. The phone interview was exactly 30 minutes. They asked about 6-8 questions, giving me only 2-3 minutes per question. I had about 5 minutes at the end for my questions. It was very direct. I was a little thrown off because the interviewer had me on speaker, so I could hear myself talking while he was typing my answers loudly. I got an email saying I was rejected about two days after the phone interview, so at least they were quick with the news.

So, first they looked at my resume and cover letter. Then I had a phone chat with one of the co-founders. After that, it was a 3-hour in-person thing. The in-person part had three bits to it. The first was with three people, and it was heavy on the technical side, asking about my past projects and tough problems I'd tackled. The second was with four people, and it was more about my personality and how I handle stuff, like teamwork, integrity, and tricky situations. During these, one person was typing notes the whole time. The last bit was a presentation I had to do, supposed to be 10 minutes, with about 8 people watching, and then they grilled me with questions for 20 minutes. After the in-person part, I had to do an at-home assignment. It involved crunching numbers in Excel, making charts, and writing up my process and answers. I really struggled with it, couldn't finish it in the time and didn't do a good job. The stuff was totally new, and I hadn't used Excel in ages, mostly used Matlab for my work. Then, I gave them my references, and they had full conversations with each one. They even asked those references for more references. It was super detailed.