Hello Georgina,
The Study has some questions regarding siblings' relationships. For household members aged 10-15 years, you will find them in the "w_youth" datafile, every two waves (1, 3, 5, 7, 9, and 11). You can check the questionnaire here (look for questions 14 and 15 on page 8): https://www.understandingsociety.ac.uk/sites/default/files/downloads/documentation/mainstage/questionnaire/wave-11/W11-youth-self-completion-questionnaire.pdf
For household members aged 16 or above, you will find them in the "w_indresp" file every two waves (3, 5, 7, 9, and 11). To find more information about the self-completion young adults' module, please check: https://www.understandingsociety.ac.uk/documentation/mainstage/dataset-documentation/wave/11/questionnaire-module/scyoungadults_w11
These questions are asked in a rotative module, therefore to see more information about the actual and planned content of the Understanding Society questionnaire, please see our Long-Term Content Plan at: https://www.understandingsociety.ac.uk/documentation/mainstage/long-term-content-plan
You can use the variable search to look up variables you might be interested in. You do not need to know precisely the variable name, you can type for example “kick” and will show any variable having the word “kick” attached to its name or label. To use variable search go to: https://www.understandingsociety.ac.uk/documentation/mainstage/dataset-documentation
Hope this helps.
Best wishes,
Roberto Cavazos
Understanding Society User Support Team