"to create estimates about families, households, and other groups, and to present other data at a household level." (source: https://www.census.gov/acs/www/about/why-we-ask-each-question/relationship/)

Tract

Survey, via mail to specific addresses

3.5 million addresses nationwide are randomly selected each year to respond to the American Community Survey. The sample size indicated below applies to the nationwide size, housing units selected for final interviews.

Random sampling method of data collection on a rotating basis, participants are legally obligated to answer all questions as accurately as possible. Privacy is protected by the Census Bureau. There is a 90% margin of error.

Relationship data is used by various tribal and government agencies to fund programs and services for households that qualify for assistance. (source: https://www.census.gov/acs/www/about/why-we-ask-each-question/relationship/) The data is publicly available and may be used for cross-community comparisons by the public, journalists, educators, businesses, and various government and nonprofit agencies.