aspect of the construct you are interested in per item. Use positive statements and avoid negatives or double negatives. Do not make assumptions about the respondent. Use clear and comprehensible wording, easily understandable for all educational levels Use correct spelling, grammar and punctuation. Avoid items that contain more than one question per item (e.g. Do you like strawberries and potatoes?). Question should not be biased or even leading the participant towards an answer. Incorporate research questions like MaxDiff and Conjoint to help collect actionable data Multi-item scales Within social science research and practice, questionnaires are most frequently used to collect quantitative data using multi-item scales with the following characteristics: Multiple statements or questions (minimum ≥3; usually ≥5) are presented for each variable being examined. Each statement or question has an accompanying set of equidistant response-points (usually 5-7). Each response point has an accompanying verbal anchor (e.g., “strongly agree”) ascending from left to right. Verbal anchors should be balanced to reflect equal intervals between response-points. Collectively, a set of response-points and accompanying verbal anchors are referred to as a rating scale. One very frequently-used rating scale is a Likert scale. Usually, for clarity and efficiency, a single set of anchors is presented for multiple rating scales in a questionnaire. Collectively, a statement or question with an accompanying rating scale is referred to as an item. When multiple items measure the same variable in a reliable and valid way, they are collectively referred to as a multi-item scale, or a psychometric scale. The following types of reliability and validity should be established for a multi-item scale: internal reliability, test-retest reliability (if the variable is expected to be stable over time), content validity, construct validity, and criterion validity. Factor analysis is used in the scale development process. Questionnaires used to collect quantitative data usually comprise several multi-item scales, together with an introductory and concluding section. Questionnaire administration modes Main modes of questionnaire administration include: Face-to-face questionnaire administration, where an interviewer presents the items orally. Paper-and-pencil questionnaire administration, where the items are presented on paper. Computerized questionnaire administration, where the items are presented on the computer. Adaptive computerized questionnaire administration, where a selection of items is presented on the computer, and based on the answers on those items, the computer selects the following items optimized for the testee's estimated ability or trait. Concerns with questionnaires While questionnaires are inexpensive, quick, and easy to analyze,