Patient and physician questionnaires, visual analogue scales, rating scales for the assessment of efficacy, effectiveness, safety, quality of life (QoL), resource use, and treatment costs are getting more and more important in clinical research. In particular, the increasing emphasis on QoL, treatment costs, real life effectiveness of drugs, and the need for patient-focused outcomes to achieve market access leads to a rise in the development and use of scales. Selection, use, analysis, and reporting of questionnaires are tasks that need to be integrated throughout the whole clinical development process, and Thomas Wagner of Trilogy Writing explains the most important steps necessary for an optimal leverage of questionnaire data.