Data play an important part in understanding systems. GroundsWell will develop an accessible, trustworthy and policy-relevant system to collate, collect, house and share data on UGBS across the three cities. These data will be used to help the whole Consortium understand the UGBS there, identify possible interventions, and then assess whether they work, for whom and why, creating feedback loops to help us continually monitor, learn and adapt what we do. Novel simulation approaches will also be used to suggest interventions, and in particular what could be effective beyond the three cities. Health economics will suggest what would be best value for money.