There's plenty of examples on the Web of the basic format a cover letter should take. There's a good template here on page 23 from Harvard. (Make sure to do it in TeX if applying for a math or comp. sci. PhD.)
Otherwise, my own personal advice ...
What not to do
The most common mistake I have found in cover letters is that they are too generic. Either they could have been written by anyone ("I have a keen interest in science. I was always curious as a ...") or could have been written for any programme ("I want to do a PhD as I believe I would be well-suited to a career in academia ..."). Keep such generic sentences to a minimum: the more of these a cover letter has, the more impersonal and unremarkable it is, and the more it leaves the suspicion that the same cover letter has been recycled for multiple applications and/or by multiple students.
Also, avoid hyperbole ("I am the best candidate for this position because ..."). You cannot know that you are the best candidate. This is an academic application, not an industrial one.
What to do
Make your cover letter personal, remarkable (i.e., stands out from other cover letters), specific to you and specific to the position at hand. Be enthusiastic. Be specific. Show that you've put thought into the position and why you are applying.
Relate your specific skill sets and previous experience to the programme you are applying for. Relate the content of specific aspects of your CV to the programme:
"During my masters, I enjoyed working on the topic of A, which relates to your programme [in this way]"
"I worked three summers at company B, where I gained experience in topic C ..."
"I visited your university in March last year and was impressed by ..."
"I read paper entitled 'D' published by your group at 'E' and was interested in ..."
"I recently published a paper 'F', which I believe compliments work by 'G' in your department on 'H' ..."
... and so forth.
Your CV cover letter is both an introduction and a sales pitch. “It should show what sets this individual apart from all others,” advises Jeffrey Stansbury, vice chair of the Department of Craniofacial Biology at the University of Colorado School of Dental Medicine in Aurora. Like any good sales pitch, your cover letter should motivate the customer to learn more about the product—in this case, you.
A good cover letter, like a good sales pitch, has several characteristics. First, like a good doctor, it does no harm: It avoids making a negative impression. Second, it demonstrates that the product suits the consumer's—your future employer's—specific needs. Third, it assures the customer that the quality of the product (you) is superb. Accomplishing all this is easier said than done. So how do you write a cover letter that will do you justice and earn an interview? First you need a plan.
If the cover letter is to be effective, it must definitely be tailored to the particular institution.—Kenton Whitmire
“A successful candidate impresses the committee right off with the cover letter and makes the committee members actually want to dig through the CV and recommendation letters to pull out the details that start to validate the positive claims,” Stansbury says. “It also provides a glimpse into the applicant’s personality and gives some guidance as to whether or not they can communicate in an organized, effective way.”
One of the most important jobs of any good sales pitch is to avoid doing harm. Some cover letters inadvertently convey negative impressions of a candidate, especially if they “look sloppy or indicate an inability to communicate in English,” says H. Robert Horvitz, who shared the 2002 Nobel Prize for physiology and medicine and has chaired search committees at the Massachusetts Institute of Technology in Cambridge. “These things can kill someone's chances," adds Kenton Whitmire, chemistry professor and former chair of the chemistry department at Rice University in Houston, Texas.
Horvitz adds that cover letters “should be neat and professional,” and should fit on one page. Whitmire would allow applicants a bit more room: The letter, he says, should be “no longer than one to two pages.” To keep it short, “the cover letter should not reproduce the information in the CV, publications list, or other documents provided," Whitmire says, "but it should be used as a vehicle to highlight those things that the candidate believes will make him or her a good match for the position at hand.”
An effective cover letter doesn't just emphasize your best qualities; it also shows how well those qualities are likely to mesh with the open position. “Applicants should begin by reading advertisements for faculty positions carefully and be sure that their background and goals are appropriate for the position in question. You lose credibility if you can't make a case that you fit the ad,” Whitmire says. “If the cover letter is to be effective, it must definitely be tailored to the particular institution.”
“There's no excuse for not writing a cover letter that shows how your education, experience, and interests fit with what the institution is seeking,” warns Julia Miller Vick, coauthor of the Academic Job Search Handbook, which is now in its fourth edition. “Not doing this would reflect laziness,” Horvitz observes. At best, Vick adds, “a form letter or one that is generic doesn't accomplish much and leaves how the application is reviewed completely up to the reviewing committee." At worst, a generic cover letter can make you seem undesirable.
“While many people applying for academic positions tend to think that the review process is an evaluation of their previous work—how good is it?—the issue that is as important is the match," Whitmire says. "How will this person fit in here? The former is necessary, but the decision to interview will often be made upon research area or some other measure of fit to the department's needs at that moment in time.”
Begin by learning about the department in general and the open position in particular. Department websites are a good starting point, but don't stop there. Go beyond the public information, and seek a sense of perspective. “It is best if candidates speak with their advisers and mentors to get some feel for the institution where they wish to apply,” Whitmire suggests. Close senior colleagues can serve the same purpose. Read beyond the job ad, and figure out what they're really looking for.
Once you've got a fix on the institution, the department, and the open position, ask yourself what abilities or special qualities a candidate needs to excel in that position. Then determine which of your qualifications and accomplishments will particularly interest this department. Think about your research plans, past research accomplishments, special projects, and previous employment.
What evidence can you put forward that your background and plans prepare you well for this opening? How well do your research interests match those described in the advertisement? How well will they complement the work of the current faculty? How will your presence there make the department better? All this information will determine what to emphasize in your cover letter.
Writing the body of the letter
Your research accomplishments and plans should constitute the body of your cover letter for a research university position. At institutions where teaching is the primary emphasis, your primary focus should be your teaching experience, philosophy, and goals—and the suitability of your research program to a teaching-focused environment.
“An outline of plans for teaching and research needs to be specific to be meaningful,” Stansbury says. Focus on your most important two or three examples of proposed research projects and innovative teaching plans, such as developing novel courses. These examples should change from one cover letter to another, as you customize your letters for different jobs.
After the body of your cover letter has been drafted, you come to the most critical step: writing an attention-getting introduction. Salespeople call this "having a handle." Your handle is what you offer that makes you especially well qualified for a particular faculty opening. For example, summarizing how well your research interests match the ones the department advertised provides an effective letter opening.
The opening paragraph should be short but more than one sentence. After you've captured the reader's attention with the handle, clearly but briefly summarize your most important—and relevant—qualifications. Anything less than a sharp focus and your readers will quickly lose interest and move on to the next application.
Closing the letter
End your letter decisively. Don't let it meander to an indefinite or weak close. A decisive close projects an image of you as assertive, confident, and decisive. It never hurts to close by requesting an interview.
Make your cover letter an example of your best writing by editing it carefully. It must be easy to read. Focus and clarity of expression in your letter imply focus and clarity of thought—very desirable qualities in a faculty member.
Then return to the critical issue: whether your research interests, other qualifications, and personality meet the search committee’s requirements. Anything that doesn’t accentuate the match should be deleted ruthlessly.
Now, set your letter aside for a day or two before editing it again. The detachment you gain from this short break will help you see what you've written more clearly. Detachment makes it easier to determine whether your paragraphs flow smoothly from one to the next. The logic that seemed so obvious when you were writing may seem much less so a day or two later. Carefully review both your cover letter and your CV to be sure the information in them is perfectly consistent. Often, a committee won't bother to try to resolve any discrepancies they find; they'll just move on to the next application.
Finally, Whitmire advises, “be sure to have your cover letter reviewed by someone [who] can be trusted and who has experience. Often, getting a second opinion about how something sounds to the reader—i.e., what they got from reading the letter, not what you intended in writing it—can be very valuable.”
This article is an updated version of an article originally published on 10 March 2006.
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John K. Borchardt
John K. Borchardt has a Ph.D. in chemistry. He is the author of the book Career Management for Scientists and Engineers.