Thiele is the Director of the CGIAR Research Program on Roots, Tubers and Bananas (RTB), led by the International Potato Center (CIP), which brings together multiple partners to improve food security and reduce rural poverty through research for development. He provides leadership to develop a shared vision, build a strong partnership among participating centers, partners and other stakeholders, support implementation of the gender strategy and manage for outcomes.

Thiele previously led social and health science research at the CIP and the Andean Change Program with over 20 national partners, using evidence from impact of participatory methods to drive policy change for more inclusive agricultural innovation. He jointly coordinated the Papa Andina Initiative which promoted new approaches to value chain innovation and repositioned native potatoes with consumers, benefiting small farmers in the Andes. He has also worked on Participatory Impact Pathway Analysis, seed systems and participatory plant breeding.