Concerns about a very old PhD advisor?

I’m thinking about taking a 70-year old math professor as my PhD advisor, in a US school. I like his teaching and research. If I don’t choose him, I would probably have to switch fields, which I can do with some pain, since I have not specialized deeply yet. My main concerns are:

• As he is far more likely than a young supervisor to pass away suddenly due to his age, how should I best plan for this scenario? What will happen to me if it happens?



• He is also far more likely to retire than a young supervisor – could his retirement (in the unspecified future) cause problems for my future career in academia, with respect to references and networking?

Related: How should I take a potential PhD supervisor's age into account, when planning to follow PhD with habilitation?

Answer

One minor counterpoint to @adipro's answer: rather than age of the professor, consider where they stand in their professional career. Age aside, you want to make sure that they're still highly active in the research community. I made the mistake of being what turned out to be my advisor's last graduate student; not a good position to be in. To present the case more generally: While all the positive points listed by @adipro were are true of someone close to retirement, they may simply might not care as much about things you care about. Specifically:

• They have no pressure to publish, and consequently, your need to publish doesn't scratch any itch of theirs


• Since they're close to retiring, they won't want to enter extensive collaborations, as they will likely be gone before the work is done. (This is referring to long, multi-year projects, not smaller stuff.)


• Their interest in grant-writing will be far less than yours, for the same reason as the preceding point; multi-year research efforts will likely complete after they're gone.

When researching potential advisors, talk to their graduate students about the number of grants they've applied for in the past two years, the number of new students they've taken on, the number of new collaborations they've started, and the like. You want to make sure they're not winding things down, as that means they'll be less interested in things you care about, such as creating new relationships, writing more papers, and finding new grants.