This guide outlines best practices for designing effective questionnaires aimed at engaging respondents and collecting accurate data. It emphasizes the importance of simplicity, neutrality, and logical flow in questionnaire design. Key recommendations include keeping surveys to a maximum of 20 minutes, organizing questions from broad to specific, and grouping similar questions together. The guide also advises on the use of a variety of question types to maintain respondent interest and suggests including quality checks to enhance data reliability. Specific sections address the importance of a well-structured survey introduction, which should include the purpose of the survey, estimated participation time, and confidentiality statements. Additionally, it highlights the need for careful consideration when designing questions for children and vulnerable groups, ensuring ethical standards are met. The document provides practical examples and templates to assist in creating high-quality surveys, ensuring that all questions are relevant and engaging while minimizing bias.