Your pool date is used to determine when you get a class date. The earlier your pool date, the higher your priority to get to class. They go strictly by pool date and availability date and have not historically maintained a big pool.

If you already have a type rating, your pool date is your interview date. If you don't have a type, your pool date is the day you finish your type rating.

Example: I interviewed and got hired without a type. A friend of mine who had his type interviewed after my DB but before I finished my type rating and was hired. His class date was assigned more than a month before mine, even though he interviewed two months after me.