Tessa Pronk is a scientific researcher in the Chemical Water Quality and Health team. She has a broad interest in complex systems and, over the last few years, has worked in various organisations on subjects in the areas of ecosystem biology, (toxico) genomics, IT and data management. She readily applies useful techniques like modelling, machine learning and text mining. She produces scripts to conduct analyses in the R programming language. At KWR she is active in data science strategy and data mining in data-intensive projects. For example, she developed a method to determine the required treatment effort for surface water and for groundwater. And, together with colleagues, she defined a method to determine the reliability of so-called ‘trigger values’, which are derived for the interpretation of bioassay results. She also contributed to producing KWR’s Hydroinformatics vision.