we have an exam thats conducted for college admission.every body takes the exam gets a rank. The top scorrer gets rank 1 and there can be multiple people holding same rank. admissions are based on simple criteria.the choice of low rank student (that is toopers) are first served seats and then high rank student's choice is taken.

we have opening and clossing rank,opening rank is lowest rank of the student (the topper's) rank that choose that college and that course.closing rank is rank of student highest rank that college allowed seat for.

given this details what are the things that need to be taken to consideration if we were to build a model that predicts next year's closing rank