survey error: focus on systematic error. total error systematic error (bias) random sampling error...
Post on 20-Dec-2015
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Survey Error:
Focus on Systematic Error
Totalerror
Systematicerror (bias)
Random samplingerror
Total Survey Error: Components
Random Sampling Error
• A statistical fluctuation that occurs because of change variation in the elements selected for the sample
Systematic Error
• Systematic error results from some imperfect aspect of the research design or from a mistake in the execution of the research
Respondent Error
• A classification of sample bias resulting from some respondent action or inaction
• Nonresponse bias
• Response bias
Respondenterror
Nonresponseerror
Responsebias
Respondent Error: Components
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
Why People Cooperate
• To be supportive/helpful
• Have a social interaction
• Curiosity
• Remuneration
Possible Cover Letter Appeals
Factors Contributing to Refusal
• Fear/anxiety
• Invasion of privacy
• Hostility toward– Survey sponsor– Topic of interview– Interviewer
Response Bias
• A bias that occurs when respondents tend to answer questions with a certain slant that consciously or unconsciously misrepresents the truth
Responsebias
Unconsciousmisrepresentation
Deliberatefalsification
Response Bias: Components
Unwillingness to Respond Accurately
• Invasion of privacy
• Time pressure and fatigue
• Physical/social environment
• Questionnaire-specific issue– Question/response wording– Layout
• Mischievous respondents
Inability to Respond Accurately
• Inarticulate
• Ignorant– Asked about other people– Asked to predict own behavior– Asked question meant for other people
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
Acquiescence bias
Extremity bias
Interviewer bias
Auspices bias
Social desirability bias
Unconscious Misrepresentation: Components
Acquiescence Bias
• A category of response bias that results because some individuals tend to agree with all questions or to concur with a particular position.
Extremity Bias
• A category of response bias that results because response styles vary from person to person; some individuals tend to use extremes when responding to questions.
Interviewer Bias
• A response bias that occurs because the presence of the interviewer influences answers.
Auspices Bias
• Bias in the responses of subjects caused by the respondents being influenced by the organization conducting the study.
Social Desirability Bias
• Bias in responses caused by respondents’ desire, either conscious or unconscious, to gain prestige or appear in a different social role.
Systematicerror (bias)
Administrativeerror
Respondenterror
Systematic Error: Components
Administrative Error
• Improper administration of the research task
• Blunders• Confusion• Neglect• Omission
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
Interviewer Error
• Subtle source of cues– Can inadvertently reinforce some responses
• Appearance of incompetence
Interviewer Error
Insufficient or poor probing
Interviewer Error
Fraud
• Why commercial houses validate roughly 20% of completed interviews
Selecting unqualified respondents
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
Ways to Handle Missing Responses
• Leave blank
• Casewise deletion
• Pairwise deletion
• Mean response
• Imputed response