Categories of candidates: The staff selection system established in ST/AI/2006/3/Rev.1 was based on a rigid hierarchy of three categories of candidates in terms of priority consideration: 15, 30 and 60-day mark candidates. If a candidate belonged to a priority category he or she was excluded from the less priority ones. Internal, non-internal and external candidates: ST/AI/2006/3/Rev.1 distinguished between: (1) internal candidates, strictly defined in section 1; (2) non-internal candidates, comprising staff members who did not fall within this definition; and (3) external candidates, those...