Which factor is taken into consideration to determine seniority if two employees hold the same rank? Seniority is the time an individual has accrued at a rank level; therefore, a senior officer is any individual who has served longer in the same office or who holds a higher rank than another position. To determine seniority between two individuals, you should look first to the individual’s rank, followed by length of service in that rank and, finally, the length of service in the department. total number of years in the field length of service in the department title of rank length of service in their current rank