OBJECTIVES: Collecting data about symptoms and health-related quality of life impacts in children aged 6-11 is particularly challenging.  Children themselves do not necessarily have the reading skills or the cognitive and recall capacity to self-report on their own, but equally parents are not always with their child or may not observe them closely enough and some symptoms are not observable.  To overcome these challenges we developed a parent-administered child-report symptom measure in which the parents helped the child read and understand the PRO items.  METHODS: Iterative rounds of qualitative concept elicitation and cognitive debriefing interviews with children (aged 6-11) and parents supported the development and refinement of daily diary instructions, items and response scales.  The resulting items were included in an observational study of 185 children (aged 6-11) who completed the diary at home for seven days in order to support the development of scoring and psychometric validation.  Feedback on the draft scales was obtained from both children and parents following the at-home completion phase, with the parent survey and debriefing focusing on how much help they had provided to the children in regards to reading, understanding, recalling and responding during the seven days.  RESULTS: The diary questions were developed to be completed by the child, but instructions indicated that the parent could help the child read and understand them.  Observation of parents helping the child and subsequent debriefing provided evidence that parental help aided the child in recalling accurately.  However, the children did push back if they disagreed with their parent’s suggested response, suggesting they were not unduly influenced.  Subsequent psychometric validation confirmed that this approach and the refined items provided valid, reliable and responsive scores. CONCLUSIONS: This PRO development provides evidence that a parent-assisted child self-report symptom measure had strong content validity and was valid, reliable and responsive to changes over time.