Overview
This lecture covers the essentials of questionnaire design in research, including question types, measurement scales, reliability, validity, layout, and best practices for achieving accurate and relevant data.
Purpose and Design of Questionnaires
- Questionnaires are tools to collect data aligned with research objectives, goals, and questions.
- They serve as measurement instruments to assess respondent differences using specific measurement levels.
Measurement Levels
- Four main measurement levels: nominal (categorize), ordinal (order/rank), interval (equal intervals), and ratio (true zero and absolute differences).
- Interval scales (e.g., Likert scales) are most common in market research questionnaires.
Likert Scales and Scale Points
- Even-numbered scales force choices (no neutral); odd-numbered allow neutral responses.
- Fewer points are better for non-experts; more points can be used with knowledgeable respondents.
Reliability and Validity
- Reliability refers to consistent, repeatable measurements.
- Validity means measuring what you intend to measure.
- Both high reliability and high validity are required for a quality questionnaire.
Principles of Good Questionnaire Design
- Questionnaires should be relevant, accurate, brief, and easy to understand.
- Use simple language, consider respondent background, and ensure timely/updated questions.
- Keep questionnaires short (ideally completed in 15–20 minutes).
Types of Questions
- Open-ended questions gather qualitative data; closed-ended questions yield quantitative data.
- Closed-ended questions include dichotomous (two options), multiple choice, and attitude scales (e.g., Likert scales).
Common Pitfalls in Question Wording
- Avoid ambiguity by using clear, concise language.
- Do not ask for over-demanding recall (e.g., remembering year-long habits).
- Avoid bias from overemphasis, leading questions, double-barreled questions (multiple concepts in one), and sensitivity around personal or illegal topics.
Layout and Structure
- Start with an introduction, product info, and duration estimate.
- Use screening questions to ensure valid respondents.
- Begin with general/warm-up questions before moving to specific, construct-related questions.
- Demographic questions are usually multiple choice or dichotomous; specific questions often use Likert scales for advanced analysis.
Key Terms & Definitions
- Questionnaire — a tool for systematically gathering data from respondents.
- Measurement level — a classification system for data (nominal, ordinal, interval, ratio).
- Reliability — the consistency and repeatability of measurement.
- Validity — the degree to which a questionnaire measures what it intends.
- Likert scale — a common interval scale for measuring attitudes or preferences.
- Screening question — a question to ensure respondents are relevant to the research topic.
Action Items / Next Steps
- Review concepts of sampling for the next session.
- Practice designing brief, clear questionnaires with appropriate measurement scales.