Questionnaire-based research in ophthalmology: questioning the quality

There have been many articles over recent years that have included questionnaires in the study methods, most recently the National Biometry Audit II.1 Much has been published both in text books and in the peer-reviewed literature concerning best practice in questionnaire design and utilisation,2, 3, 4, 5 and while questionnaires are clearly an invaluable research tool when used appropriately, poorly constructed questionnaires produce meaningless or misleading responses, and lack of rigour in analysis leads to the formation of invalid conclusions.6