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Final annual family weight


FWEIGHT is a 6-digit numeric variable.


FWEIGHT is a variable based on the Final Annual Weight in the original NHIS public use files. This weight should be used for many analyses at the family level, particularly with variables for which information was collected about family characteristics.


Creating FWEIGHT requires using independent estimates of the number of families from a reliable source such as the U.S. Census Bureau in order to perform post-stratification adjustments in a manner similar to what was done for the person-level weights. However, such independent estimates do not exist.

As a result, the NHIS used the "principle person" method to create family-level weights. The person weight with the smallest ratio adjustment within each family was used as a proxy for the family-level ratio adjustment. This method is believed to provide a more accurate estimate of the total number of U.S. families than either the use of other person weights within the family or the use of no ratio adjustments at all. Therefore, the Family weight contains factors for selection probabilities at the household level, household non-response adjustment, and several ratio adjustment factors that are applied to all person weights.

Users should review the documentation for extracted variables--most notably the "Weights" section toward the top of each variable description--to ascertain which weight is the appropriate choice for a given survey year. See the User Notes on the use of sampling weights for additional information.


This variable is comparable for all years.


  • 1997-2018: All families


  • 1997-2018