Hello Michaela,
UKHLS recently released a family matrix data file “xhhrel”, where you can identify family connections across different households over time. The xhhrel file creates an individual-level cross-wave file of all sample members (those who were ever enumerated as part of the study) that contains familial relationship identifiers reported over the survey period for each sample member. I think you could use this file to identify grandparents.
The file, xhhrel, only includes information about the relationships and some sample member demographic information, such as sex, year of birth, etc. This data file will need to be combined with the main survey data files to get additional information about the sample members and their relatives. There is a syntax provided in the user guide to do this. After linking the main study information to the familial relationship, you will have all UKHLS data related to, in this case, grandparents.
Further details about xhhrel data structure and linking to the main survey can be found here:
https://doc.ukdataservice.ac.uk/doc/6614/mrdoc/pdf/6614_family_matrix_xhhrel_user_guide.pdf
For Understanding Society’s key variables, including recommendations on socioeconomic & demographic characteristics, please check here: https://www.understandingsociety.ac.uk/content/understanding-society-key-variables
Hope this helps
Best wishes,
Understanding Society User Support Team