Abstract.Although often neglected, model validation is a key topic in flood risk analysis, as flood risk estimates are characterised by significant levels of uncertainty. In this paper, we discuss the state of art of flood risk models validation, as concluded from the discussion among more than 50 experts at two main scientific events. The events aimed at identifying policy and research recommendations towards promoting more common practice of validation, and an improvement of flood 15 risk models reliability. We pay specific attention to the different components of the risk modelling chain (i.e. flood hazard, defence failure and flood damage analysis) as well as to their role into risk estimates, to highlight specificities and commonalities with respect to implemented techniques and research needs. The main conclusions from this review can be summarised as the need of higher quality data to perform validation and of benchmark solutions to be followed in different contexts, along with a greater involvement of end-users in the debate on flood risk models validation. 20

In educational policy research, linking specific practices to specific outcomes is an important (though not the only) goal, which can bias researchers (and funders) toward employing purely quantitative methods. Given the context-specific nature of policy implementation in education, however, we argue that understanding how specific practices lead to specific outcomes in specific conditions or contexts is critical to improving education. Qualitative comparative analysis is a method of qualitative research that we argue can help to answer these kinds of questions in studies of educational policies and reforms. Qualitative comparative analysis is a case-oriented research method designed to identify causal relationships between variables and a particular outcome. Distinct from quantitative causal methods, qualitative comparative analysis requires qualitative data to identify conditions (and combinations of conditions) that lead to a particular result; it is context driven, just as many educational reforms must necessarily be. We contend that qualitative comparative analysis has the potential to be of use to educational researchers in investigating complex problems of cause and effect using qualitative data. As such, our aim here is to provide a general overview of the characteristics, processes, and outcomes of qualitative comparative analysis. In so doing, we hope to offer guidance to educational researchers around how and when to use qualitative comparative analysis, as well as recommendations for current educational issues that could be investigated with qualitative comparative analysis.