A Dynamic Three-Stage Co-Design Process for Developing an Assessment Scale for Children with Neurodevelopmental Conditions

Background: Involving patient partners and diverse stakeholders in research is increasingly recognised as essential for aligning outcomes with patient priorities and improving service design. Co-design brings together individuals with lived experience, professional insights, and technical knowledge to improve research tools. Objective: This case study describes the process of co-designing a user-friendly assessment scale for children's developmental issues. It highlights the collaborative effort to integrate the unique perspectives of diverse stakeholders, including families and service providers. Methods: A three-stage iterative approach was used to collect qualitative data gathered through semi-structured interviews engaging adults with lived experience, parents, clinicians, and disability service providers. In the initial stage, stakeholders' priorities, barriers, and enablers related to the developmental assessment process were identified, and a prototype was developed. While the second stage used targeted feedback on a prototype to refine items, structure, and usability. In the final stage, participants evaluated the scale's face validity, user-friendliness, and practical utility, with a focus on its applicability in clinical and support settings. Discussion: This study demonstrates how an inclusive, iterative co-design process can yield an assessment tool that genuinely addresses the needs of its users. Unlike traditional consensus-building approaches, which may overlook minority voices, this method actively engaged underrepresented perspectives, including those of families and clinicians from diverse backgrounds. Conclusion: This study describes an iterative co-design process that prioritises diversity of voices, including seldom-heard perspectives, instead of focusing on consensus. The method discusses the importance of inclusivity in co-design resulting in an assessment scale that reflects unique experience and perspectives of its users.