The SHIW is a representative sample of the Italian resident population.
The sample design is similar to the Labor Force Survey
conducted by ISTAT (the Italian national statistics agency).13 Data
are collected through personal interviews. Questions concerning the
whole household are addressed to the family head or the person
most knowledgeable about the family finances; questions about individual
incomes are answered by individual household members
wherever possible. The unit of observation is the family, which is
defined to include all persons residing in the same dwelling who
are related by blood, marriage, or adoption. Individuals selected as
“partners or other common-law relationships” are also treated as
families