The Finnish Society for Environmental Social Science (YHYS, Yhteiskuntatieteellisen ympäristötutkimuksen seura ry) brings together practitioners and users of environmental social science in Finland.YHYS organizes annually a colloquium and a science-policy dialogue. The fall colloquium is Finland's flagship international scientific meeting in the field of environmental social science. The Policy Dialogue is organized in collaboration with the Forum for Environmental Information, featuring dialogue between researchers, decision-makers and members of civil society on topical environmental policy issues. YHYS organizes annually a competition to award outstanding Master's thesis. The aim of the competition is to find and reward distinguished thesis from the field of environmental social sciences. The prize has been named after Yrjö Haila, the society's long-term chair and Finland's first professor in environmental policy.