The letter must include the basic terms of employment, including the salary offered. More difficult is describing the position. If the position offered is a tenured position, or a tenure-track position, then it is simple. However, few research positions are tenured. Qualifying research positions, therefore, can include positions that do not have a fixed duration but are the sort of position in which the alien can expect permanent employment.
Private employers face additional requirements.
The employer must show that they employ three full-time researchers and that research conducted by the employer has resulted in documented accomplishments. INS rules provide no information on how a private employer can document research accomplishments. The best evidence possible should be submitted, which would include any patents issued to researchers at the institution, and articles published by employees.