Abstract: BACKGROUND: Cognitive interviewing is a technique that can be used to improve and refine questionnaire items. We describe the basic methodology of cognitive interviewing and illustrate its utility through our experience using cognitive interviews to refine a questionnaire assessing parental understanding of concepts related to preterm birth. METHODS: Cognitive interviews were conducted using current best practices. Results were analyzed by the multidisciplinary research team and questionnaire items that were revealed to be problematic were revised. RESULTS: Revisions to the questionnaire items were made to improve clarity and to elicit responses that truly reflected the participants understanding of the concept. CONCLUSION: Cognitive interviewing is a useful methodology for improving validity of questionnaire items, we recommend researchers developing new questionnaire items design and complete cognitive interviews to improve their items and increase confidence in study conclusions.