“Big data” and “data science” are terms we hear more and more these days. The idea that we can use these vast amounts of information to understand and analyse phenomena, and find solutions to problems, is gaining prominence, both in business and academia. Cathie Sudlow, Professor of Neurology and Clinical Epidemiology at the University of Edinburgh, has been at the forefront of enabling health-related research using ever-increasing datasets. She tells presenter Jim Al-Khalili why this type of research matters, how the COVID-19 pandemic changed attitudes towards data in healthcare, and why the NHS gives the UK a big advantage when it comes to population-wide studies. Over the course of her career, Cathie has held a variety of roles at different organisations, and she is currently Chief Scientist and Deputy Director at Health Data Research UK. She believes that there is no room for prima donnas in science, and wants her field to be open and collaborative, to have the most impact on patients’ lives. Produced by Florian Bohr.