[Update: added a couple of useful points.] This is the time of year when prospective graduate students are visiting different universities, deciding where they will spend the most formative years of their scientific lives. Amidst the enthusiastic sales pitches, I try to make sure to remind everyone that the odds of success are long -- there is a bottleneck that shrinks as you go from grad school to postdoc to junior faculty to tenure. Probably the biggest hurdle is the leap from postdoc to junior faculty; it's easier to get tenure once you're a professor (statistically speaking) than to become a professor in the first place. But it's not guaranteed! As many of you know, I was denied tenure myself. This actually puts me in a pretty strong position to talk about the ins and outs of what it takes to succeed, having seen lack-of-success (is there a word for that?) up close and personal. I've avoided talking too much about this topic, partly because armchair psychologists have trouble resisting the temptation to take anything general I would say and attempting to match it to specific people and aspects in my own case, despite a pretty thorough lack of familiarity with the facts. On the other hand, maybe I can offer some actually useful guidance to people who are trying to do something difficult and important for their future lives. So here goes: how to get tenure. But first, caveats. My own experience from grad school on has been at top research places, so those are the only ones I can speak usefully about; the situation will generally be very different at places that put more of an emphasis on teaching, for example. So really I'm talking about places that think of themselves as being in the top 10 or so in their research fields. And of course, to every set of rules there are exceptions; it's not hard to find people who violated one or more of these guidelines, so don't take them as written in stone. Every case, and every department, is different. Finally, don't think of these as too bitter or cynical; I'm simply trying to be honest, with perhaps a small slant to counteract some of the misinformation that is out there. (This misinformation doesn't usually arise from willful lying, but from the slightly schizophrenic nature of the mission of research universities; see The Purpose of Harvard is Not to Educate People.) I'm generally in favor of the tenure system; like democracy, it's the worst system out there, except for all the other ones that have ever been invented. With all that throat-clearing out of the way, let's get down to brass tacks. Here is the Overriding Principle: what major research universities care about is research. That's all. Nothing else. But even once you recognize that, there is still some craft involved in shaping your research career in the right way. This isn't the place for me to pass judgment on this principle; I'm just elucidating its consequences. This is a how-to manual for the real world, not a roadmap for Utopia. You'll be pleased to learn that there are actually two different routes to getting tenure, so you can choose which one works better for you. The first one is simple to describe, and comes down to a single suggestion:
Be a productive genius. This deserves to be classified as a separate technique because, for the small number of easily-recognized true geniuses out there, the rest of the suggestions below are beside the point. Do whatever else you like, as long as you are revolutionizing the field on a regular basis. It's worth stressing the word "productive," though. The trash heap of history is littered with geniuses who thought it was beneath their dignity to actually produce anything; that won't fly, generally speaking, in this game. So if the genius thing is working out for you, great; just be sure to put it to productive use, and you'll be fine.
The rest of us schlubs, on the other hand, need a more explicit checklist. So here's what ordinary people should try to do if they have a junior faculty job at a major research university, and would like to get tenure.
Do good research. This is obvious, right? So I'm not going to belabor it.
Be prolific and reliable. No, tenure is not given or denied simply on the basis of how many papers you write. But… it doesn't hurt. More importantly, if there is some standard of productivity in your field, try to maintain it all the time. Don't have "a bad year." Because if you have one bad year, who knows how many bad years you'll have in the future?
Be technically sound. Quality is sometimes hard to judge. But among different types of quality, it's a bit easier to recognize "technical" ability -- whether it's doing fearsomely complicated calculations, or huge computer simulations, or what have you -- than more "creative" or "imaginative" contributions. (To be clear: creativity is good, not bad. It's just hard to quantify.) George Gamow, a very creative guy, had trouble getting a job at a top place because there were worries about his technical ability. And he practically invented the early universe as we know it.
Make an impact in the field. It's not enough to do good work; your work has to be recognized as good. The single most important part of your tenure file is the letters from experts at other universities, comparing you to the best young people in your area. If any of them come back saying "I've never heard of this person," it's the kiss of death.
Get your name on something. A slight exaggeration, but if you have something named after you -- a theorem, an experiment, a model -- it's a big help. The larger principle is that your contributions should be specific, not vague. Good: "she invented model A." Bad: "she did major work in B, and was one of the first to think about C." In Hollywood terms, have an elevator pitch. It's easier for people to think about what you've done if it can be summed up in a sentence. When people ask "what was your major contribution?" have an answer ready.
Don't be too well known outside the field. I hate to say this, but the evidence is there: if you have too high of a public profile, people look at you suspiciously. Actual quote: "I'm glad we didn't hire Dr. X; he spends too much time in the New York Times and not enough time in the lab." And that's the point -- it's not that people are jealous that you are popular, it's that they are suspicious you care about publicity more than you do about research. Remember the Overriding Principle.
Don't write a book. This follows partly from the above; if you're contemplating writing a popular book, and aren't sure whether it will negatively impact your chance of getting tenure, you're probably too far gone for this list to even help you. But it's worth a separate bullet point because even textbooks are beyond the pale. (Probably the worst thing I personally did was to write Spacetime and Geometry.) You might think that a long volume filled with equations that provides a real service to the community would help your case. It won't; it will hurt it. Why? Because while you were writing that book, you weren't doing research. Catching on? (Obviously I'm writing from a field where research is conveyed solely through papers, not books; if you're in a field where the serious research is contained within scholarly books, then by all means write all the scholarly books you can.)
Bring in grant money. Thanks to Steinn in comments for mentioning this one. Getting grants is a big help, because (1) money is good, and (2) it's extremely quantifiable.
Take outside offers seriously. If another top place is interested in you, don't just jump on it, but don't blow them off, either; pursue the possibility, and let it be known that you are pursuing it. If you would really like to stay where you are and worry that they will let you go without a fight, squelch that worry. Maybe they will let you go, but if so, there is a strong possibility that they weren't that interested in keeping you. (Duh.) Also, it always helps to be popular; professors are people too, and can be influenced by the opinions of others.
Don't worry about teaching, leadership, organizing, etc. I don't think being good at these things actively hurts you, although I did once hear a senior faculty member say that he was negatively predisposed to candidates who had good teaching evaluations. (He was joking, I think.) Why? Because you're spending time on something that isn't research. But generally it won't hurt, it just won't help. You will typically be told (as I was) something like "teaching isn't really important, but if your case is very close, it can help put you over the top." Everyone agreed my case was very close, and my teaching was among the best in the department; it didn't help. The point is simple: this stuff is not research.
Choose your hobbies wisely. This is a bit more subjective, but I think there is some truth here. Even the highest-pressure departments in the world don't think that faculty members can't have any hobbies outside their work. But here is the paradox: you are better off if your hobbies are nothing like your work. Permissible hobbies include skydiving, playing guitar, or cooking. Suspicious hobbies include writing of any sort (novels, magazine articles, blogs), programming or web stuff, starting a business, etc. Why? Because there's a feeling that this kind of activity represents time that could be spent on research. I don't think blogging has quite the stigma it once did, although I have heard senior faculty members say they would never hire someone with a blog. But it's a symptom of a willingness to spend your intellectual energies on something other than doing research.
Friends are good; enemies are bad; indifference is fine. There can be an element of personal politics involved in tenure decisions, although this is usually exaggerated by outsiders who don't know much about the substantive issues. It is important to have people within the department who are respected and will make a strong affirmative case for you. It is also bad to have people within the department, especially respected ones, who are against you. (Tenure usually doesn't just require a majority vote, it requires a strong consensus within your department.) But interestingly, it doesn't matter that much if many people in the department don't care one way or the other. They are usually happy to go along with the respected people closest to you academically, especially if they indicate strong support. You don't need to be friends with everyone, just the right people.
Don't dabble. Another slightly counter-intuitive one. You might think that, while most of your research work is in area A, the fact that you wrote a couple of papers in area B will be taken as positive evidence of your breadth and intellectual strength. Very wrong. What will actually happen is that your work in area B will be compared to the best people in the world who spend all their time thinking about area B, and you will probably come up wanting. Even worse, it will be taken as evidence that your interests may wander over time -- so that, whereas you were hired to be an expert in area A, maybe in a few years you won't be doing that at all. Kiss of death. Deep down, there is a strongly anti-intellectual strain within academia; you were hired to work in a specialty and that's what they expect you to do. Once you get tenure, of course, you can do whatever you want; so it's important that the department be reassured that you don't want to do anything else.
Again, some of this may seem a bit cynical, but I'm trying to put things as strongly as possible so the message isn't garbled by well-intentioned pieties. It's certainly possible to get tenure while violating some of the above rules, but the trend should be clear. Let's put it this way:
Places hire on hope, and fire on fear.
When you get hired, the facts that you are interdisciplinary and a good teacher and a strong leader all work to your advantage, because these really are good things. The people who hire you are sincere when they give you compliments for these qualities. What you don't know is that, at the faculty meeting where they voted to hire you, inevitably someone said "Why are we thinking so hard about this? It's a junior faculty job. Let's just take the risk, and if they don't work out they won't get tenure." The tenure decision is very different than the hiring decision. When you get hired, everyone can afford to be optimistic; you are an experiment and you might just hit paydirt. When you come up for tenure, the prevailing emotion is one of worry. Even the biggest departments don't get to hire that many people; tenured slots are extremely valuable and rare commodities. They are committing to you for the next three decades. And what scares them to death is that you will stop being a productive researcher. And any evidence that you enjoy doing things other than research within the field in which you were originally hired is, like it or not, possible evidence that you will drift away from your core mission once you achieve tenure. We all know senior people in good departments who are no longer productive; don't give your department any reason to suspect that you will become one of those people. Of course, there are things in life that you might judge to be more important. These aren't guidelines about how to live your life, only about how to get tenure. It's up to you to decide whether following them represents a sacrifice you are not willing to make. Nobody gets into this job for the money or the glory; career considerations aside, you have to make sure you're having fun and chasing your passions. Good luck!