Pioneer in developing guidance for environmental and later sustainability reporting and guidance for providing assurance on it:
- Framework for assurance engagements on environmental reports in PhD
- Criteria development for European Sustainability Reporting Awards and ACC Awards
- Guide to Sustainability Reporting of the Dutch Accounting Standards Board Dutch Standard 3410 Assurance engagements related to sustainability reporting
- FEE (European Federation of Accountants) Research and Discussion papers
- Member of the core team of various Global Reporting Initiative projects (Guidelines from its start in 1997 and High Five project for SME reporting
- Was worldwide the first to do research on assurance reports in relation to environmental reporting and how they could be improved. Currently the focus is on sustainability reporting and the research is going from exploratory research towards explanatory research.
- Has performed innovative research on the relationship between internal control (COSO framework) and ISO 14001 and how environmental management systems can be improved to provide reliable in- and external information; Has chaired the development of a postgraduate programme CSR management and CSR auditing at Erasmus University Rotterdam.