Waitlisting means that the graduate selection committee considers you qualified for their program, but for some reason your application wasn't strong enough to make the final cut. (For example, some committee members may have voted for your admission, while others may have saved their votes for candidates they felt were stronger.)
The upside of getting waitlisted is that you haven't been denied admission, and you can take steps to try to upgrade your status to "admitted."
The downside is that, if the school that waitlisted you is your first choice, you may feel left in limbo, unable to make plans until you have further information.
From the school's perspective, a waitlist is important to make sure that the incoming class is both full (every spot filled) and balanced (diverse in age, background, experience, etc.).
Most schools admit more students than they can actually accommodate, as they expect a certain percentage of admitted applicants will not enroll. If enough admitted applicants opt not to enroll, then spots will eventually open up for waitlisted applicants also. For example, if a school can accommodate 75 new students, they may admit 100 applicants (25 more than there is room for). If 26 of these admitted applicants opt not to enroll, that opens up one more spot for people on the waitlist.
Usually waitlisted students aren't ranked—but they may be categorized according to background and experience (categories will vary according to a school's priorities). So if an admitted applicant chooses to enroll elsewhere, the admissions office will aim to fill their spot with someone from the waitlist with a similar biographical profile.
As a waitlisted applicant, your choices are to:
How to decide whether to walk away or to wait involves gathering facts and reflecting on your own priorities.
Facts you'll want to gather include:
Reflecting on your short- and long-term priorities and needs will help you discover whether you can—logistically speaking—wait around.
If you are willing to wait for admission, you'll increase your chances by letting your admissions counselor know that you are still enthusiastic. The letter you received indicating your waitlist status should include a deadline for informing the admissions office about your continued interest in the school. Follow all the guidelines you've been given.
If you suspect or are told that you're on the waitlist because your test scores weren't competitive, or because you haven't had the prerequisite professional experience, do what you can while you are waiting to improve your test scores by retaking the test(s), and to enhance your professional experience through volunteering in a relevant field.
Do not pester the admissions office; however, you can politely check in with your admissions counselor and let them know of your efforts. Send a brief letter or email with your news, or with a clarification that will strengthen your bid for admission. Be very professional in all correspondence; it still counts as part of your application.
Because not everyone on the waitlist is going to wait around for admission, your chances for a favorable outcome increase the longer you are willing to wait. If a spot does open up, admissions professionals are eager to admit candidates who are most likely to enroll. If you stayed in (brief, polite) contact with the admissions office, they will be aware of your continued interest.
You may find yourself waitlisted for one or more schools. The way you handle yourself really can make a difference if space opens up. Applicants who follow directions to be in touch by a certain date and who maintain short, courteous, regular (but not overzealous) contact are seen as more interested candidates than those who never check in. But keep in mind that waitlisted applicants who push and prod for a commitment may find themselves disappointed. A system is in place to handle the waitlist process, and programs cannot always be as accommodating as applicants would like. Patience, courtesy, and consistency are key qualities to show at this point.