A Guide to Your Rights & Responsibilities as a Graduate Applicant per the Council of Graduate Schools
If a prospective graduate student is made an offer of financial support (scholarship, fellowship, traineeship, assistantship) by an institution who is a signatory of the Council of Graduate Schools' April 15 Resolution, that student can not be made to render a decision about accepting that offer before April 15 unless they do it of their own accord.
If a representative from an institution requires that you accept an offer before April 15, they are violating the intent of this resolution. You have until April 15 to make a binding commitment to accept an offer, even though you may decide that it is wise to accept an offer much earlier.
Click below to read the April 15 Resolution and see which institutions are signatories of this resolution.
Please also be courteous and be sure to inform other schools of your decision as soon as possible, but no later than April 15.