After university, Sue worked for development and environmental charities, becoming freelance in 1990 when she established Equilibrium Research in partnership with UNEP-WCMC Fellow Nigel Dudley. Equilibrium works on a wide range of issues to promote successful area-based conservation. Much of their fieldwork in recent years has been focused on the development of management effectiveness assessment for protected areas, the diversity of benefits from protected areas and governance approaches. A guiding influence has been the implementation of the CBD’s biodiversity targets. Equilibrium Research has published over 200 books, reports and papers, many of which have been developed following field research and development.