Researchers in the WIPH Centre for Primary Care Clinical Effectiveness Group have developed an address-matching algorithm, to link patient health records with geospatial information. The algorithm, published on 8 December, will enable accurate research into how an individual’s household and surroundings affect their health, with planned studies into childhood obesity, and whether multi-generational households are at greater risk from Covid-19. The algorithm, ASSIGN (AddreSS MatchInG to Unique Property Reference Numbers), allocates a Unique Property Reference Number to GP records, giving every patient address a standardised format that enables pseudonymised linkage to other sources of data.