/ HASS Requirement / HASS-D Requirement / Lottery

The HASS-D Lottery Algorithm

The lottery algorithm begins by assigning all students their first-choice classes. Then, for each overenrolled class, it randomly pulls out students until the enrollment is down to maximum number of students allowed for that section. The remaining students will be allowed to remain in the class.

For each student who has been pulled out, the algorithm then moves down his or her list of alternate choices, assigning the students to their highest ranked class with space still available. If all of a student's alternate choices are full, that student will have to appear in person at the first meeting of a class listed with space available. Typically, more than 85% of students receive their first choice class, and fewer than 4% receive none of their choices.

Since the algorithm only looks at the list of alternate choices after the decision to remove a student from the first-choice class has already been made, making alternate-choices does NOT reduce the student's probability of receiving his or her first choice. It does, however, make it more probable that the student will receive a desirable class in case he or she is lotteried out of the first-choice class.