The demand for affordable housing resources from the federal, state, and local government far exceeds the supply. When PHAs have more eligible applicants than vouchers or other public/subsidized housing openings available, they create waiting lists. Waiting lists make it possible for PHAs to keep records of eligible families for easy access when new resources/vouchers become available. PHAs can choose to keep the waiting list open and accept applications at any time or choose to only open the waiting list for brief application periods. Waiting lists are often closed because they are too long - containing more families than the PHA will be able to serve in the near future. A family's position on a waiting list can change depending on what waiting list preferences they meet.