As this edited volume shows, there are many ways to improve survey data collection and survey data analysis. Paradata are one of the tools used in this endeavor. Across the world, data collection agencies use paradata to monitor or manage their data collection, or if they are not currently using paradata, they are engaged in finding out how such data can be used.1 But before going into detail on why and how paradata can be used, a quick definition might be in order for those readers unfamiliar with the term.