Transparency on underlying values is needed for useful equity measurements

Decision-makers increasingly invoke equity to motivate, design, implement, and evaluate strategies for managing flood risks. But there is no objective definition of equity. This pluralistic setting calls for transparency about underlying values, but this practice is uncommon. Here, we review how equity is measured by surveying peer-reviewed publications that explicitly state an interest in equity in the context of flood-risk management. We develop a simple taxonomy for how transparent measurements can be defined. We map reviewed measurements to this taxonomy. Finally, we offer guidance on how the pursuit of a clear and consistent quantitative evidence base about equity can become more widespread in flood-risk research and beyond.