The household projection is based on the population figures of the main variant of the population forecast for Austria and the federal provinces. The household representation ratios, which are linked to the population projection to calculate the household figures, and the shares of the population living in institutional households are derived from the results of the 2011 register census. These ratios are held constant throughout the projection period. Thus, this projection measures the purely demographic impact on the future number and structure of private households; changes in household numbers are solely the direct result of population trends. Societal trends reflected in age- and gender-specific household formation are not included for reasons of comparability of the 2011 register census with historical censuses.