In awarding scholarships, the Foundation Board of Trustees considers the nominee's field of study and career objectives and the extent to which that individual has the commitment and potential to make a significant contribution to his or her field. This is judged by letter of references, essays written by the student, and prior research experience. The number of scholarships awarded per region depends on the number and qualifications of the nominees for that region. The regions are defined as each of the 50 . states , the District of Columbia , Puerto Rico , and, considered as a single entity, Guam , the United States Virgin Islands , American Samoa , and the Northern Mariana Islands .