Understanding Society covers the whole household and researchers may want to link household members within waves and across waves.
Households are uniquely identified in each wave by w_hidp, a wave specific variable with a different prefix for each wave. It can be used to link information about a household from different records within a wave, but cannot be used to link information across waves. Since the composition of households can change between waves, the data do not include a longitudinal household identifier. For example, a_hhresp can be linked with a_indresp using a_hidp but not with b_hhresp.
Individuals are identified by the personal unique identifier (pidp), which is the same in all waves and can be used to link information about a person from different records belonging to one wave, or to link information from different waves. The cross-wave person identifier pidp is consistent across the harmonised BHPS and UKHLS files. Additionally, individuals are identified by w_pno – the person number within the household. The combination of w_hidp and w_pno is unique for each individual only in datafiles for wave w. For example, ba_indresp can be linked with h_indresp using pidp; a_indresp can be linked with a_indall using pidp or using a_hidp a_pno. But a_indresp cannot be linked with b_inbdresp using a_hidp a_pno.
To help researchers link families we have created a family matrix data file (xhhrel). This data file identifies all family relationships across the Study, allowing researchers to see where people and households connect. For further information read the Connecting family members and households over time web page.
Tips for analysts:
Take a look at the syntax for help in linking household members and individuals.
Pointers to significant others in the household are listed under the Index Terms Person Identifiers and are part of the wider group of variables listed as Key linking variables.
If you’re struggling to link the files get in touch with our User Support team.
