Simpson has worked on the Afghan, Eritrean, Ivorian, Somali, Syrian and Zimbabwean refugee crises in Afghanistan, Egypt, Israel, Jordan, Kenya, Liberia, Libya, South Africa and Turkey, on the plight of internally displaced people in Chad, the Democratic Republic of Congo, Yemen and Sudan’s Southern Kordofan State. Based in Geneva, Simpson regularly meets with the UN refugee agency (UNHCR) to advocate on Human Rights Watch's refugee work worldwide and to press the agency to enhance its protection of refugees. Before joining Human Rights Watch, Simpson worked as a human rights lawyer in London and then as an advocate and protection officer with Medecins sans Frontieres, the Norwegian Refugee Council and the International Rescue Committee's Emergency Team in numerous countries, including the Central African Republic, Colombia, Darfur, Sierra Leone, southern Sudan, Sri Lanka, Tajikistan and Uganda. Simpson holds law degrees from Southampton (UK) and Rouen (France) Universities and from the College of Europe in Bruges (Belgium).