More and more surveys are conducted both qualitatively and quantitatively to approach complex issues. During this online lecture, the added value of this and the challenges you may encounter in doing so will be discussed from various angles. For example, how do you ensure good cooperation between quantitative and qualitative researchers? In which research areas can mixed-methods research offer an appropriate solution? And what innovative ways are there to shape mixed-methods research? SCP, Sciensano (Belgian public health research centre) and I&O/Ipsos will share their experiences. This lecture will be held in Dutch.