OPNAVINST 1427.2A.
All officers graduating in May or June have their date adjusted to the graduating date of the USNA class, with the USNA valedictorian taking the top spot. The rest are determined by percentile of class standing. Officers for whom class standing cannot be determined will be junior to all other officers. Tiebreakers will be: 1. total commissioned service, 2. date of rank, 3. Regular Officers over Reserve Officers, 4. date of birth, 5. alphabetical order by last name.
Lineal numbers are assigned at O2. O1s do not have lineal numbers or precedence.
FY20 convening orders allowed for fifteen percent of selectees to be merit reordered to the top of the list regardless of DOR, zone, or precedence. Big deal, as it makes a difference of years between one officer and another (O5 with 18YCS promoted to O6 before another O5 selected at 20YCS, putting it on this November vs. next year).