The survey process described in this book has different levels of precision at each of its many stages. On the one hand, sampling theory, which was described in the previous chapter, has been developed to a relatively high degree of sophistication such that, with due care, sampling error can be reduced to pre-specified acceptable levels of precision.  The same cannot be said, however, about the design of the survey instrument. The challenge of this stage of the survey process is dealing with the fact that it is much more of an art form than a science. Indeed, the design of survey forms fits very neatly the definition of an art form as "an established form of composition (e.g. a novel, sonata, sonnet, etc.)" (Concise Oxford Dictionary). Here we have an art form which, like a sonata, has rules which must be followed to ensure the best possible results, but which is free to adapt to the constraints imposed by the overriding objectives of the study and to the skills of the survey designer.

This chapter on Survey Instrument Design covers the following topics:

5.1        MORE TRADE-OFFS IN TRANSPORT SURVEY DESIGN

5.2        SCOPE OF THIS CHAPTER

5.3        QUESTIONNAIRE CONTENT
               5.3.1        Length of the Questionnaire
               5.3.2        Relevance of the Questions
               5.3.3        Reasonableness of the Questions
               5.3.4        The Context of Questions about Trips
               5.3.5        Questionnaire Design to Maximise Trip Recording

5.4        PHYSICAL DESIGN OF SURVEY FORMS

5.5        QUESTION TYPES
               5.5.1        Classification Questions
               5.5.2        Factual Questions
               5.5.3        Opinion and Attitude Questions
               5.5.4        Stated Response Questions

5.6        QUESTION FORMAT
               5.6.1        Open Questions
               5.6.2        Field-Coded Questions
               5.6.3        Closed Questions

5.7        QUESTION WORDING
               5.7.1        Use Simple Vocabulary
               5.7.2        Use Words Appropriate to the Audience
               5.7.3        Length of Questions
               5.7.4        Clarify the Context of Questions
               5.7.5        Avoid Ambiguous Questions
               5.7.6        Avoid Double-Barrelled Questions
               5.7.7        Avoid Vague Words About Frequency
               5.7.8        Avoid Loaded Questions
               5.7.9        The Case of Leading Questions
               5.7.10        Avoid Double Negatives
               5.7.11        Stressful Questions
               5.7.12        Avoid Grossly Hypothetical Questions
               5.7.13        Allow for the Effect of Response Styles
               5.7.14        Care with Periodicity Questions
               5.7.15        Use of an Activity Framework
               5.7.16        Flow of the Question
               5.7.17        Always Use a Pilot Test

5.8        QUESTION ORDERING

5.9        QUESTION INSTRUCTIONS
               5.9.1        Self-Completion Surveys
               5.9.2        Personal Interview Surveys