The Change in U.S. Average Household Size Attributable to Population Aging: Decomposing the Reciprocal of a Demographic Rate

Mike Hollingshaus , University of Utah

Average household size is a critical measure that impacts government budget allocations and anticipated demand for services. Population age structure affects household size, but little research has examined its historical contributions. This paper decomposes changing average household size, as measured by persons-per-household (PPH), into behavioral and age-structural components. Since age-specific PPH is undefined for children, direct decomposition is impossible. I therefore develop and apply a straightforward method to decompose the reciprocal of a demographic rate. Historical U.S. decennial census data show PPH has decreased monotonically since 1850, and decomposition reveals most of this change (85 percent) can be attributed to population aging. Distinctive patterns appeared during the Baby Boom, and recent trends show a return to dynamics observed during the early 20th century. Results suggest average household size will continue to decrease as the U.S. population ages, a finding that further informs household and population estimates and projections.

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 Presented in Session 4. Marriage, Family, Households, & Unions