Post on 19-Dec-2015
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Random Sampling Error
A statistical fluctuation that occurs because of chance variation in the elements selected for the sample.
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Systematic Error
Systematic error results from some imperfect aspect of the research design or from a mistake in the execution of the research
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Respondent Error
A classification of sample bias resulting from some respondent action or inaction
• Nonresponse bias
• Response bias
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Non-response Error
• Non-respondents
– Refuse to cooperate
– Not-at-homes
• Self-selection bias
– Over-represents extreme positions
– Under-represents indifference
• Varies by type of interview
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Why People Cooperate
• To be supportive/helpful
• Have a social interaction
• Curiosity
• Remuneration
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Factors Contributing to Refusal
• Fear/anxiety
• Invasion of privacy
• Hostility toward
– Survey sponsor
– Topic of interview
– Interviewer
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Response Bias
A bias that occurs when respondents tend to answer questions with a certain slant that consciously or unconsciously misrepresents the truth
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Unwillingness to Respond Accurately
• Invasion of privacy
• Time pressure and fatigue
• Physical/social environment
• Questionnaire-specific issue
– Question/response wording
– Layout
• Mischievous respondents
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Inability to Respond Accurately
• Inarticulate
• Ignorant
– Asked about other people
– Asked to predict own behavior
– Asked question meant for other people
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Inability to Respond Accurately
• Faulty memory
– Only ask about recent events
– Problem with questions about behavior over time (e.g., frequency)
– Telescoping
• Everything happened yesterday
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Acquiescence bias
Extremity bias
Interviewer bias
Auspices bias
Social desirability bias
Unconscious Misrepresentation: Components
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Acquiescence Bias
A type of response bias due to some people tending to agree with all questions or to concur with a particular position.
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Extremity Bias
A type of response bias due to response styles that vary from person to person; some people tend to use extremes when responding to questions.
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Interviewer Bias
A response bias that occurs because the presence of the interviewer influences answers.
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Auspices Bias
Bias in respondents’ answers due to being influenced by the organization conducting the study.
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Social Desirability Bias
Bias in responses caused by respondents’ desire, either conscious or unconscious, to gain prestige or appear in a different social role.
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Administrative Error
• Improper administration of the research task
• Blunders
• Confusion
• Neglect
• Omission
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Administrative Error
• Interviewer cheating - filling in fake answers or falsifying interviewers
• Data processing error - incorrect data entry, computer programming, or other procedural errors during the analysis stage.
• Sample selection error -improper sample design or sampling procedure execution.
• Interviewer error - field mistakes
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Interviewer Error
• Subtle source of cues
– Can inadvertently reinforce some responses
• Appearance of incompetence
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Interviewer Error
Fraud
• Why commercial houses validate roughly 10-15% of completed interviews
Selecting unqualified respondents
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Checklist for Unacceptable Questionnaires
• Major portions of questionnaire or key questions left unanswered
• Evidence that respondent did not understand instructions or did not take task seriously
• Missing pages• Respondent not qualified for target
population• Questionnaire returned after cutoff date