Only by measuring and understanding the scale of slavery can we effectively tackle it. We use Multiple Systems Estimation (MSE) and other methodologies to estimate slavery prevelance in the UK and around the world. We do this in combination with our use of mobile phone, population and behavioural data, in order to better monitor prorgress to achieving Sustainable Development Goal 8.7 (ending slavery by 2030).We also conduct in-depth analysis around key intersecting issues for example the relationship between slavery data and data on conflict, democracy, governance, and women's rights, so we can better understand the potential root causes of enslavement. You can read a recent report by our researcher, Professor Bernard Silverman, here: "The R package modslavmse for multiple systems analysis". This accompanies Bernard's R package of programs for MSE for modern slavery prevalence.