Anybody can write down a list of questions and photocopy it, but producing worthwhile and generalisable data from questionnaires needs careful planning and imaginative design

The great popularity with questionnaires is they provide a “quick fix” for research methodology. No single method has been so abused.1

Questionnaires offer an objective means of collecting information about people's knowledge, beliefs, attitudes, and behaviour.2 3 Do our patients like our opening hours? What do teenagers think of a local antidrugs campaign and has it changed their attitudes? Why don't doctors use computers to their maximum potential? Questionnaires can be used as the sole research instrument (such as in a cross sectional survey) or within clinical trials or epidemiological studies.

Randomised trials are subject to strict reporting criteria,4 but there is no comparable framework for questionnaire research. Hence, despite a wealthof detailed guidance in the specialist literature,1^–3> 5 ^w1-w8 elementary methodological errors are common.1 Inappropriate instruments and lack of rigour inevitably lead to poor quality data, misleading conclusions, and woolly recommendations.^w8 In this series we aim to present a practical guide that willenable research teams to do questionnaire research that is well designed, well managed, and non-discriminatory and which contributes to a generalisable evidence base. We start with selecting and designing the questionnaire.