There are some notations on your boarding pass that you need to know.

Other than your flight number, boarding and departure time, gate, and — if applicable — your frequent flyer status, which means your account has been entered into your record, there’s another notation that most people miss.

It’s a sequence number, or SEQ — an internal listing that’s posted on your boarding pass.

It lets the airline agent know the order in which passengers checked in for a particular flight—and it also determines the pecking order as to who gets bumped first in terms of an oversale — otherwise known as involuntary denied boarding.

One more reason to check in early so you have a low sequence number.