PUBHBIO 7225 Lecture 2
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Assuming the observation unit is a person, questions should be …
Simple and clear
Specific, not general
(not good) “Have you ever been attacked?”
(better) “Has anyone ever attacked you in any of these ways: (a) With any weapon, for example, a gun or knife, (b) With anything like a baseball bat, frying pan, scissors…”
Related to the concept of interest
Carefully ordered
Responses to a question may be unduly influenced by question(s) that preceded it
Usually best to ask more general question first, followed by specific question(s)
Questions should be (cont.)…
Not leading or “loaded” questions
Not written as double-negatives
(not good) “Do you favor or oppose not allowing drivers to use cell phones while driving?”
(better) “Do you agree with laws banning cell phone use while driving?”
Not double-barreled
If closed-ended, all response options are available
If multiple-choice/forced-choice, response options are mutually exclusive and exhaustive
Survey Questions (Part 1)
Four ways we could get information from a sampled person, called the survey mode:
High-level differences include:
Cost
Use or non-use of an interviewer
Availability of visual aids
Enforcement of “skip patterns”
Issues with the frame
Types of biases likely to be present
Availability of (and types of) paradata
Survey completed in-person via an interviewer, traditionally via door-to-door canvassing (considered “gold standard”)
Pros:
Cons:
Frame Considerations:
Survey completed by respondent with paper and pencil (“PAPI”), usually sent via mail
Pros:
Cons:
Frame Considerations:
Survey completed over the phone – in practice, usually “CATI” (Computer Aided Telephone Interview) where computer is used by interviewer (not by respondent)
Pros:
Cons:
Frame Considerations:
Survey completed online, often called “CAWI” (Computer Aided Web Interview)
Pros:
Cons:
Frame Considerations:
Survey Questions (Part 2)
Historically, survey methodologists described errors as “Sampling Errors” and “Non-Sampling Errors”
More modern approach is the Total Survey Error approach
Total Survey Error = difference between population parameter (the truth) and the estimate of that parameter based on a sample survey
Two types of survey error:
Adapted from Groves et al. (2009), Survey Methodology, 2nd Edition
Some sources of measurement error:
lying
not understanding or misinterpreting the question
forgetting/recall bias
different responses in different survey modes
interviewer effects
different responses to different interviewers
social desirability
satisficing (choosing “easy” answers to reduce response burden)
question order
question wording
All these representation-related errors can lead to Selection Bias
Arises when some part of the target population is not in the sampled population
Occurs when the actual probabilities with which units are sampled differ from the specified selection probabilities
Is most obviously a problem for non-probability samples, but can also arise with probability samples
OPAS Sources of Error
PUBHBIO 7225