A data workshop was held at the Greentree Estate on Long Island to bring together a range of stakeholders to think about what we need to ‘know’ to achieve SDG 8.7. The programme included a mixture of plenary and break-out sessions. This included strategies for improving the measurement of modern slavery and child labour, strategies for generating useful knowledge around risk and vulnerability factors and ways to identify new data sources to fill existing data gaps. The United Nations University had previously conducted a short survey to help understand what the potential users of the Alliance 8.7 Knowledge Platform would like to get out of it. The main findings of this survey are reflected in the Framing Discussion Paper which was discussed in the workshop.