The Management policy of early notification to the students, requiring multiple assignment runs with incomplete information, has consequences to the overall process and results. Tests have shown the overall score suffers after submitting the returning and new students separately. Getting student preferences into the first assignment run is a major priority -- this run has the maximum degrees of freedom for making good matches.
Notified only of their hall, however, students assigned a room early may still be moved. We are free to change their bed within the same hall, and possibly their hall if a higher choice becomes available. Were anybody to be moved to a worse hall -- not one of the student's requested halls, or a lower ranked available hall -- the whole run would be unusable. To try to prevent this from happening, automatic upgrading is implemented as a constraint with an extremely large `worse hall' penalty.
Preliminary tests show that secondary runs with automatic upgrading can help to compensate for the disadvantage of doing multiple runs, but still they do not compete with the quality of results from a single larger run. This upgrading feature has yet to be used in production, as discussed in Section 4.2.4 (page ).