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Choices in the Data

The student's primary contribution to the assignment process is filling out and turning in the Residency Application form. Students who remain dorm residents over their college career increase their chances of getting the room they want. Keeping the same room is an overriding choice -- essentially a hard constraint for DAO. Students also improve their chances of getting their choices by reserving a place in line early. To be placed with a friend in the same room, roommate requests should be mutual and compatible.

Baffled Roommates
Baffled as to why two friends, less than a month apart in age, were not placed together after requesting each other, the same halls, same music preference, same study habits, and turning in their applications at the same time, the Area Coordinator discovered one was a smoker and the other objected to smoke. Clearly, the smoking error (60,000) vastly outweighed the incomplete group error (4,588) for these two first timers. A smoke compatibility verification, added in version v1.15, revealed over a hundred roommate requests with the same problem. Reported as exceptions, Ranville is now alerted to such conflicting data. Understanding why this happened, future orientations will stress the importance of compatible choices when requesting a roommate.

Since constraints are cumulative, the more choices a student makes, the better their assignment tends to be because they can produce larger errors on mismatches. We found cases where a student who requested the same hall for all three preferences had a better chance of success than a more senior student who had only filled in their first choice. We surmised a similar phenomenon existed with roommate requests -- a student with five roommate requests was more often satisfied than the student with only one best friend. Attempting to level the playing field, we added configurable options to duplicate students' hall choices and roommate requests in DAO version v0.45. When the roommate duplication option was tried in early Fall 2000 tests, Ranville noticed students with mate requests and less seniority were given preference over students with more seniority and no roommate requests. Roommate duplication was not used.

Multiple roommate requests also come into play in a new way as adjoining rooms are now considered when placing students. For the student who chooses a double room, the bestfriend option tries to place their first valid roommate listed in the same room rather than split them across a suite.

Spending Choices Foolishly
In Fall 2000, we saw first-time residents requesting the prize apartment-style single rooms (about 28% of the total bed space) for their first and second choices and the other popular hall with adjoining rooms (about 18% of the total bed space) as their third choice, get a single in an unrequested dorm; students behind them in line who requesting the adjoining double rooms as their first and second choices and the less desireable hall for their last choice actually got their first choice. The person who gets their paperwork in early should at least get their third choice, according to Ranville, even if they choose to spend their first choices foolishly, at the expense of the wiser student behind them. Rather than leaving some of these students' bad choices to chance, Ranville fixed their requests to get them into the hall they `deserved'.

Two conflicting important constraints could hurt the student's chances of getting into their requested area. For example, students who request the apartment-style dorms should also request a single room so the two choices do not conflict. Sometimes students fail to indicate they are a non-smoker while requesting a non-smoking special living option (see table on page [*]). Occasionally students designate the same music type for both their preference and objection, or request a roommate of the opposite gender -- usually a data entry problem. All these exceptions are reported to and remedied by the Housing Reservations staff before assignment processes are run.

next up previous contents
Next: Chances: The Simulated Annealing Up: Choices: The Dorm Assignment Previous: Multiple Assignment Runs   Contents
elena s ackley 2002-01-20
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