The Planning Ratio Estimation Program (PREP) utilizes the American Community Survey PUMS records. The annually updated PUMS are used to provide clients with samples based on housing and demographic information. Examples include Newly Moved-in Households, Recently-Built Units, 55+ Households, Transit Commuter Households Living in Multifamily Units, Low and Moderate Income Households, and so on.
PREP defines 54 core housing configurations and an extended list of 90 configurations. It calculates demographic multipliers for each housing configuration whenever the PUMS records are big enough for sample estimation.
There are four basic types of demographic multipliers: People, School, Traffic, and Income. The most common and widely used demographic multipliers are the average number of occupants and school-age children per household.