Focus groups are a useful method for co-creation and co-design because they allow you to interact with customers in a structured and moderated way. Through focus groups, you can gain insights into customer problems, needs, and motivations, test and validate your assumptions and hypotheses, generate and evaluate ideas and concepts, collect feedback and suggestions for improvement, observe customer reactions and emotions, and build rapport and trust with customers. Additionally, focus groups can be combined with other methods such as surveys, interviews or observations to complement and enrich your data.