Those who study human behaviour have a unique advantage over other scientists. The natural scientist studying a galaxy or an atom can observe, measure and sometimes experiment, but only the social scientist can ask questions of their subjects. As we shall see, this furtner source of information brings both new opportunities and new problems. Anyone can ask questions; the sociological skill lies in asking the right questions and making sense of the answers you get

Of all the instruments in the sociological toolbox, questionnaires and interviews are probably the best known. These are the two main formats within which sociologists ask questions. The key difference is how the questions are presented; interviewers conduct their questioning face-toface with the respondent while in the questionnaire the individual responds to questions that are written on a form.