Why do you want a PhD?

The New York Times published an astonishing and depressing article yesterday about the lengths to which some Chinese students and their families will go to gain admission to elite academic institutions. Egalitarianism aside, their stance is painful to read about because it suggests such dependency on "prestige" and the belief that a famous degree will open more doors. (To be fair, I'm almost completely interpolating, but I'm not sure what other explanations are plausible.) A famous degree probably does open more doors immediately after college, but I'm confident the extra opportunity is not worth the price these families are paying. I went to one of these fancy-pants schools for undergrad; it was fantastic, and my peers were a constant source of inspiration, but I've no illusions that these famous schools are the surest or likeliest path to a wonderfully successful life*.

Moreover, I wonder when these students and their families will, if ever, switch strategies. How much prestige in life is enough? When can you turn away from opportunity? Would it be acceptable to go to one of these schools and then become a massage therapist? (I have a friend who did something like this. She told me she loved watching the looks on the faces of the parents of students at our private prep school alma mater when they heard she went to Elite Ivy U and now dances professionally at parties.) If the purpose of higher education at these institutions were more focused on serving society, I might have some sympathy for disappointment with less cerebral or influential careers; however, the majority of people seem to consider these educational opportunities largely as springboards for personal gain**. Massage therapy might arguably be more beneficial to others than many positions in finance.

This post is a round-about way of exploring motivations for getting a PhD. I assert that the following reasons are weak and insufficient:

• A PhD degree is prestigious. It is prestigious in some circles, but the prestige is shrinking or nonexistent among most of your probable reference groups. Regardless, if you need to feel that other people think you're smart, you're not so cut out for the intellectually humbling experience of research. Also, you will probably make a really annoying and arrogant collaborator.
• A PhD degree will help me land a tenure-track academic position. It's true that you can't become a professor in most countries without a PhD or its equivalent. However, the majority of people with PhDs in science who plan to become tenture-track professors do not actually become tenure-track professors, at least in the U.S. and Europe. This is not for lack of trying. The job market is terrible, and there's no reason to believe it will improve considering the trends in higher ed. This topic is probably worthy of multiple other posts.
• A PhD degree isn't a bad thing to get while I figure out what I want to do. Actually, there are several reasons why it might be worse than doing nothing. (1) In a philosophically and emotionally vulnerable phase of your life, you will effectively be drinking academic Kool-Aid. In many departments, academia is still the only socially acceptable career goal for graduate students, and many professors disingenuously promote the idea that anyone can get a professorship. These conditions will warp your thinking and preferences. (2) The financial and professional opportunity costs are large. Especially if you might want to work in industry, it might be better to start doing bench work right away, and you can discuss opportunities for advanced degrees with your coworkers. Many PhDs trying to go into industry find themselves overqualified or "incorrectly" qualified, i.e., industry would rather train someone cheaper who has more practical experience. (3) A PhD requires excessive time and focus, leaving you few opportunities to explore other directions.

It might be good to think about what percentage of your motivation can be attributed to the factors above. In my view, the only acceptable conditions for doing a PhD are:

• I want to learn how to do research, and
• I don't mind substantially reducing my immediate and probably lifelong earning potential.

The second point might not matter now, but consider that it might when you're older, trying to start a family, and have minimal savings. Unfortunately, there are huge gender differences here: a study of U.S. postdocs revealed that women are more apt to think about the material consequences of their professional choices on potential future families than men are, and this thinking might lead to the high attrition of female postdocs. (The implication is that low salary and career instability are an indirect source of gender discrimination in academia--I'll write more about finances during grad school in a future post.) In certain fields such as engineering, the PhD can precede huge increases in salary, but this is not guaranteed.

In summary, do your research before doing your research: Learn about the potential trajectories of your career and any large field-related trends before committing to a PhD. Do not procrastinate on thinking about what you want to be doing with your life in five and ten years. And remember that though the commitments can be annulled, it's better to leave sooner rather than later. If you've been exceedingly driven your whole life or have family members who have been encouraging you (explicitly or implicitly) to get a PhD, think especially hard about your motivations.

*Even if you define success as something lame like "get lots of money" or "become famous."

**That said, I think the more elite/wealthy the institution, the more apt they are to emphasize the importance of social service to their students and to make such career paths more accessible. I'm not sure if their students are more apt to take advantage of these opportunities, however.

Filter Feeding

One of the most fun and occasionally overwhelming aspects of research is learning about other discoveries in the field. Conferences can help, but to avoid local bias and increase coverage, it's best to rely on a steady diet of published papers. In the first year of grad school, you might not know exactly what your field is, and the papers might look like a sea of esoteric trivia. It's like that for a while. Gradually, as you hone in on particular questions and read more deeply, the mass will start to take shape, and you'll be able to understand better how one paper relates to another.*

The cliché is that reading articles is like drinking from a firehose, and it's clearly worse if you're totally new to the field and have to catch up. (I'm also assuming you know what your "field" even is. One can pick from many firehoses.) To develop a sense of which questions are popular and how they're being answered, I think it's handy to use a RSS aggregator to manage four kinds of feeds:

1. The contents of important journals: If there's a journal that everyone in your lab reads, whose articles you always find fascinating, or whose contents are potentially immediately important (arguably, Science or Nature), you might choose to subscribe to their complete tables of contents.
2. Articles that have important keywords: A journal's impact factor can have a notoriously poor correlation with the quality and utility of individual articles published in it. It's a bad and slightly dangerous habit to think that because something was published in a so-so journal, the research is only so-so. For maximum thoroughness, set up a feed at a citation database that notifies you of any article published with a specific keyword.
3. Articles that have cited important/cool articles: If you've found an article that you think is the coolest thing ever (or wrongest thing ever, and you're working on a response), create a citation alert to notify you every time the article gets cited. It's a good idea to do this for your own articles, too, and any articles that are central to your research.
4. Articles published by an important person in your life: Basically, your adviser, though you can cite-stalk anyone. Some advisers are prolific and do not communicate very much with their labs, and you might be interested in their work. 

I think the second feed is the most important. With this approach, I stumbled on an article that mentioned an amazing and unique data set. The authors were not well known outside their country, and I'd never before heard of the journal in which the article was published. I wrote the authors and offered to collaborate, and they kindly agreed to share all their data with me. This happened in a "hot" field, and it surprised me that no one else had asked before to collaborate with them. My take-away (with n = 1) is that you can get an edge if you read broadly.

For those new to RSS feeds**, the first step is to choose an aggregator that you like. I use Google Reader, which I can open from Gmail. I use it in conjunction with Helvetireader, which is easy on the eyes and pretty perfect for skimming titles and abstracts. Popular citation databases include Web of Knowledge, PubMed, Google Scholar and Scopus. (The first and last require an institutional subscription.) If you haven't yet, do some sample searches in each to find out which is best for your field. Even if you don't have access to proprietary journals or databases, you might be able to do something useful with open-access journals, PubMed, Google Scholar, and/or arXiv.

Currently, my feed gets roughly 200 articles/week. I'm not sure this is good, but one of my research subjects is very popular. For the vast majority of the articles, I don't read past the title; with a subset, I read the abstract very closely; and for the remaining few, I read the abstract and article itself (to some degree). Figuring out the right ratio of skimming to reading has been a big challenge for me. It would be interesting to see how scientists' reading habits vary.

*To a certain extent, these shapes are always changing--it's hard to know what methods or analogous systems might inform the questions we're pursuing.
**I'm not sure if it would be helpful for me to write a post that outlines this process in detail. Please let me know if you'd like one.

Writing the Statement of Purpose

A statement of purpose for a science PhD program is nothing like the essays one might write for college, medical school, or undergraduate scholarships. Those essays can read more like entries for a personality contest, where the implicit objective is to try to look like a sparklier snowflake than the other applicants. For a science PhD application, the statement should focus more on your ideas than you.

Female Science Professor (a.k.a. FSP) has written two fantastic essays (here and here) on what a statement of purpose should and should not look like. She has reviewed hundreds of statements and is a tenured professor, whereas I've seen only a few dozen and am a postdoc. Weight our advice appropriately.

The core of my advice is captured by FSP's statement that

I don't believe that the depth of your love for science, or any pursuit, correlates with how early you discovered that love, so I find such descriptions of childhood inspiration unconvincing in an application for graduate study in the sciences.

There is no need to make it sound like you've been fated to go into science, do research, or develop novel nonparametric methods to study Arctic sand mites. There's no set path to becoming a scientist. If you haven't seen it already, you'll notice that many successful professors haven't had "linear" careers, though nonlinearity is more common in some fields than others.

Similarly, don't argue that the fact that you got an A+ in ReallyHardUpperLevelScienceCourse, scored perfectly on a standardized test, or had an IQ of 155 at age 10 means you're qualified to be a scientist. (I've seen the last one, though the numbers have been changed to protect the naïve.) First, your recent grades and scores will speak for themselves, and only your parents continue to find your childhood adorable. Second, the argument suggests a belief that scientists are born more than they are made. It's far better to describe how you've pushed yourself to learn particular skills--a talent required for a sustainable research career--than to say that you're smart. One could argue that the A students in particular need to show that they can push themselves, make mistakes, and learn.

The statement should mostly be about the ideas in the field that interest you and questions you'd like to investigate. It's fine to reference particularly germane papers that excite you (do not simply cite the most classic papers in the field that were assigned reading in undergrad), but you do not need to spell out a fixed plan of research for the next five years or cite for the sake of citing. Describing interesting questions in several thematically related areas is fine. Briefly describe how your past experiences have prepared you for research, and briefly discuss what attracts you to this particular program. That's it!

The writing should be extremely clear, but it does not need to be cute or clever. The quality of your writing matters; no adviser likes rewriting students' draft manuscripts. In my opinion, the sine qua non of writing advice remains Strunk & White's Elements of Style. I suspect every native English speaker either loves that book or has been conditioned through repeated exposures to ignore it; I wonder how many non-native English speakers know it and find it helpful. Working to improve your writing now is just win all around.

There's not much to sweat, really.