Behavioural science methods are increasingly used to design and evaluate public policies that better reflect human behaviour and decision making. However, there is a lack of standardization in selecting and labelling these methods, making it difficult for policymakers to choose the appropriate one for a specific policy context. To address this, this working paper proposes guidelines and a visual roadmap, including five key questions to guide the selection of appropriate methods, and seven different experimental or non-experimental methods to choose from. The aim is to provide a simple and practical framework for policymakers to choose the most fit-for-purpose method for their policy context.