At a later stage in the development process, patients are involved again through cognitive debriefing interviews to test their understanding of the draft questionnaire. This step is particularly important because all items must convey to patients exactly what they are intended to convey, and the items must be interpreted in the same way by all patients in the target population, regardless of age, gender, or ethnicity. Although this may appear obvious, in reality it can be very challenging to word an item in such a way that all patients interpret it as intended, and cognitive debriefing interviews sometimes reveal interpretations that the developers of the instrument had not imagined possible. The transcripts of these cognitive debriefing interviews are analyzed, and items are reduced or modified based on the results. In addition to the wording of the items, it is necessary to develop instructions to go with the items, to carefully consider the format of the questionnaire and its mode of administration, and to set the scoring method.