The data on rooms were obtained from answers to long-form questionnaire Item 37, which was asked on a sample basis at both occupied and vacant housing units. The statistics on rooms are presented in terms of the number of housing units with a specified number of rooms. The intent of this question is to count the number of whole rooms used for living purposes. For each unit, rooms include living rooms, dining rooms, kitchens, bedrooms, finished recreation rooms, enclosed porches suitable for year-round use, and lodgers rooms. Excluded are strip or pullman kitchens, bathrooms, open porches, balconies, halls or foyers, half-rooms, utility rooms, unfinished attics or basements, or other unfinished space used for storage. A partially divided room is a separate room only if there is a partition from floor to ceiling, but not if the partition consists solely of shelves or cabinets.
This measure divides the rooms distribution into two equal parts, one-half of the cases falling below the median number of rooms and one-half above the median. 'Median rooms' is computed on the basis of a standard distribution (see the "Standard Distributions" section under "Derived Measures"). In computing median rooms, the whole number is used as the midpoint of the interval; thus, the category "3 rooms" is treated as an interval ranging from 2.5 to 3.5 rooms. 'Median rooms' is rounded to the nearest tenth. (For more information on medians, see "Derived Measures".)
To calculate aggregate rooms, a value of "10" is assigned to rooms for units falling within the terminal category, "9 or more." (For more information on aggregates, see "Derived Measures".)
Data on rooms have been collected since 1940. In 1970 and 1980, these data were shown only for year-round housing units. Since 1990, these data are shown for all housing units. In Census 2000, this question was asked on a sample basis. In previous decennial censuses, the question on rooms was asked on a 100 percent basis.