Oh....no, no, no.....seniority at our place is historically based on whatever criteria is favorable to the candidate with the most political connections. I was hired with a lateral (always go to the bottom of their class) who was related by marriage to the then-mayor, and they tried a sneaky move where he suddenly appeared at the top of our class on the seniority list after a couple of months. It turns out they snuck him into city hall the morning of the day we were sworn in, and had him sign the book about 5 hours before everyone else. The rest of my class had to collectively threaten a lawsuit to get it straightened out. They also pulled a cute move by calculating the sergeant's exam scores in a completely different, bizarre manner than usual in order to place the relative of another political big shot ahead of everyone else.