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Surveys. Alfred Kobsa University of California, Irvine. When to chose a survey. Scope of problem very clear Questions can be clearly formulated at a concrete level
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Surveys Alfred Kobsa University of California, Irvine
When to chose a survey • Scope of problem very clear • Questions can be clearly formulated at a concrete level • Complex/holistic answers not needed. Checking pre-formulated answers is sufficient (plus occasionally one or two free-text sentences). • Mailing lists with current addresses available • Specific location not required • Answers from many users needed • Answers needed quickly • Broad geographic distribution of respondents • Anonymity required
Steps • Identify the objectives of the study (in writing) • Select the target audience • Select the form of announcement and response collection (email, physical mail, web [☛survey websites], in person, phone) • Decide how to analyze the data (software, statistical tests if any) • Brainstorm questions (closed questions, open questions) • Formulate questions (mind double-barreled, double negatives, leading or loaded questions, and questions with self-image, acquiescence and social desirability bias) • Use existing surveys (e.g. System Usability Scale SUS ) • Consider capabilities of survey site • Reduce question set • Pilot test and revise your questions!
Problems to consider • Non-representative sample population (☛ compare demographics of respondents with demographics of names in mailing list and normalize answers accordingly) • Low response rate (☛ pre-announcement, personalized cover letter, reward, short survey, few open-ended questions, self-addressed envelope w/ stamp, multi-mode reminders) • Self-selection bias of respondents based on topic (☛ hide your study goal among more general questions) • Honesty (☛ reverse-code questions, check consistency, discard data) • Self-incrimination (☛ emphasize“harmlessness”, impunity, anonymity) • Social desirability bias, self-image bias (☛ phrase questions carefully, use several questions for same concept, go for facts and not habits, attitudes or intentions) • Sensitive questions (☛ explain their purpose, do not make answers mandatory, offer broad answer bins)
Response format • Closed-ended questions • Single-choice or multiple-choice (include “other” + “explain”) • scalar value (“on a scale from 1 to 5, how would you rate…”) • Likert* scale: [1 … n] or [-n -n+1…. n-1 n] (typically n = 5, 6 or 7) with mid-point, or without (forces respondents to take a stance) with verbal “anchors” for first and last value only, or for all/some values including first and last** • Ranking scales (e.g., sorting by priority) • Open-ended questionsShould be kept to a minimum and optional since • they may cause users not to fill in or abandon a questionnaire • if users answer them, they only provide brief answers • answers are hard to evaluate • *) pronounced like “ike” in the US, but like “lickert” elsewhere (also by Mr Likert himself and his son) • **) First and last value anchors should be “extreme”