Tierney is a Programme Associate with the Global Initiative Network (GI-TOC), where she contributes to programmatic efforts for the Secretariat. Prior to joining GI-TOC, she was an intern at the United Nations Population Fund (UNFPA) within the Population and Development Division, focusing on advancing global census and population data initiatives.

Her professional background also includes roles in international education and research, notably at the USAWC, Dickinson College and the American International School of Salzburg.

Currently, Tierney is completing her Master of Science in Global Demography at the University of Vienna. Her research focuses on the social determinants of birth registration in UN-classified Least Developed Countries (LDCs). She is particularly interested in utilising demographic research to support maternal health and to strengthen Central Vital Registration Systems, reflecting her commitment to leveraging demographic knowledge for human development and global progress. Tierney holds a Bachelor’s degree in International Studies from Dickinson College and remains based in Vienna, where she would like to advance the field of demography in support of the United Nations sustainable development goals.