What you need to know...
So what is the difference between the terms 'deferral' and 'wait-list?'
When a student applies early decision or early action they are either accepted, rejected or deferred by mid-December. A deferral means that their application will be considered again as part of the regular decision applicant pool, with decisions published by mid April.
When a student applies regular decision they are either accepted, rejected or wait-listed by mid April. As students apply to a number of institutions, colleges and universities don't always know whether they are first choice, so they will retain a waiting list should any of those who have been offered places choose to go elsewhere. After the 1st of May - when students confirm their choices - those on the wait-list will be informed if there is a place for them.
What does this mean for you, and what should you do?
It is relatively safe to say that if you have been deferred or wait-listed, you have met the academic entry criteria of your chosen institution, but other applicants were simply deemed a better fit. Each college or university will then 'second choice' you, should any of their other applicants drop out.
If the institution in question is your top choice, and you definitely intend to go there if offered a place, there are a number of things that can bolster your application, and that may help to get you get bumped further up the queue:
Do...
1. Contact the university to ask them what your chances are, if there are particular criteria that they are working with and if they will accept further contact from you in support of your application. If you can, and haven't already done so, visit the institution.
2. If the institution is happy to receive an update from deferred / wait-listed candidates, write a letter to the admissions office expressing your commitment to their institution and explaining why you are a good fit - and what you will bring to the community. Use this letter as an opportunity to update them on any achievements (sporting, test results, extra-curricular events etc.) you have made since your original application. And remember, written communication is really important to US colleges and universities - make sure this letter is engagingly written, grammatically correct and typo/spelling error free.
3. Ask a teacher, or myself to write an update recommendation on your behalf that will also detail recent achievements, relate current academic performance and support the letter that you yourself have written.
4. If you haven't already had one, you may be able to request an interview with a local representative (or over Skype) to allow the institution to get an even better feel for who you are.
Don't...
1. Ask why you have been deferred or wait-listed, you are unlikely to get an answer and the reason is probably that there was someone better - which isn't great for anyone's self-esteem.
2. Contact the institution with updates unless their policy says that they are happy to accept them - Princeton, for example, usually request that wait-listed students make no further contact and wait to hear from them.
3. Be unrealistic with your expectations - the vast majority of candidates who are deferred or wait-listed will not ultimately be offered a place.
Finally, remember that you have options - you were good enough to meet the criteria for this institution, but the numbers were what scuppered your application this time. You will have a second choice option that will give you an excellent level of education and provide you with experiences and a friendship group which will become important parts of your future life. Make sure that you secure this place (which will mean a deposit) in case your wait-list / deferral efforts don't work out.