I did industry research and then chose to return for a CS PhD at CMU. A few thoughts on why I chose to do a PhD. In industry research, it’s hard to work on the same problem for long. Timelines change and product incentives shift. As a result, it’s difficult to really develop deep insights into one particular area of research. During a PhD, you can plan out multiple years of research without worrying about external factors. You want to work on diffusion for five years? Simply go do it. This is perhaps the number one reason to do a PhD. Second, industry typically gives you little control over collaborators. It’s difficult to know who you’re going to work with and, once you’re there, you can’t really pick and choose either. At some point, everyone has worked with someone they absolutely do not want to work with. In a PhD, the talent density is incredibly high. I’ve had the opposite problem where I simply want to work with too many people. But, if you do encounter someone you don’t want to work with… simply don’t work with them. Lastly, let’s say you do work for a top-lab where you’re surrounded by brilliant people and everyone has the same long term vision. Guess what… almost everybody around you has a PhD. Not only does this mean you have to prove you are at a PhD level, but mentally it’s annoying knowing that everyone else has a PhD and you don’t. I firmly believe that you can succeed without a PhD, but it’s definitely an uphill battle. Of course, there are many downsides to doing a PhD, most notably money and compute (aka money). Nowadays, a pattern I’ve seen work very well is 2-3 years in industry before the PhD, just to provide yourself some money and comparison. Everyone I know who has done this has been very successful. At the end of the day, the PhD is about buying time and freedom of choice. Whether that’s worth it is up to you.