The linked dataset contains Covid-19 Infection Survey (CIS) ID's and linked Valuation Office Agency (VOA), and Energy Performance Certificate (EPC) data. In addition, analysts can link the dataset to the main CIS attributes dataset, which includes test results from nose and throat swabs, antibody test results and key demographic information by sub-regions. This linkage is intended to enable investigation into household composition as a driver for testing positive for COVID-19 and spread of infection, using factors such as property type, floor space and number of rooms. Linkage method: The VOA and EPC data is first linked to AddressBase using UARN and then to matching CIS household IDs with UPRN. Processing: The CIS, VOA, and EPC data undergo cleaning before linking. Scottish and Northern Ireland Addresses are removed from the CIS-VOA file, and duplicate CIS records are removed using household ID. The CIS-VOA file then undergoes additional clerical checking to remove any rectify conflicts where a CIS household is matched to more than one VOA record. Limitations: Only linked data for England and Wales is currently available.