1 Class 7 Pretesting measures and considerations in modifying or adapting measures November 10, 2005 Anita L. Stewart Institute for Health & Aging University

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Class 7

Pretesting measures and considerations in modifying or adapting measures

November 10, 2005

Anita L. Stewart Institute for Health & Aging

University of California, San Francisco

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Steps 5-7: Pretesting and Adapting

1. Specify context 2. Define concept for your study3. Identify and review potential measures for

a) conceptual and psychometric adequacyb) practicality and acceptabilityc) translation available if needed

4. Select best candidates5. Pretest selected measures in your groups6. Choose best ones based on pretest results, OR7. Adapt if necessary to address problems this week

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Purposes of Pretest by Context

In your search for measures, can look for evidence of pretesting– Evaluate whether measure was pretested and

adequacy of methods When creating a battery of measures

– You can conduct pretest to help you decide between alternative measures

When using specific measures– You can conduct pretest to identify problems

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Example of Measure Undergoing Cognitive Testing

Consumer Assessment of Health Plans Study (CAHPSTM)– Harris-Kojetin et al., 1999 (in readings)

Describes extensive pretesting in developing and refining the CAHPSTM

Provides example of good pretesting

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Step 5: Pretest in Target Population Pretesting essential for measures being applied

to any new population group– Especially priority measures (e.g., outcomes)

Pretest is to identify:– problems with method of administration,

respondent burden, procedures– problems with questions or response choices

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Types of Pretests

General debriefing pretest (N=10) In-depth cognitive interviewing

(N=5-10 each group) Large pretest (N=100)

– test measurement properties prior to major study

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Types of Pretests

General debriefing pretest (N=10) In-depth cognitive interviewing

(N=5-10 each group) Large pretest (N=100)

– test measurement properties prior to major study

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General Debriefing Pretest

Goal

– Identify problems with the procedures

– Estimate time needed to complete instrument

– Identify serious problems with items Procedures

– Subjects answer entire questionnaire

– At end, debrief

– Close to true task

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Debriefing Questions After Administration of Survey..

Ask respondents: Were any questions confusing? Which words were hard to understand? Which questions were difficult to answer?

caused distress? Was questionnaire too long? Confusing instructions?

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Patient Acceptance Scale

6-item scale about burden of a survey Negative affect burden

– Feeling embarrassed, upset, annoyed, uncomfortable

Questionnaire length Ease of answering questionnaire

Zimmerman M et al., Med Care, 1994;32:603-608

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Example of General Pretest to Select Best Measure of Patient Satisfaction

Compared 4 questionnaires on– Response rates, missing data, completion time,

patient ratings of the questionnaire 10 evaluation items at end of questionnaire

– Clarity of questions, ease of finding an answer, questions about unimportant issues, ease of completion, too long, layout confusing, lacked important questions

Perneger TV et al., A randomized trial of four patient satisfactionquestionnaires Med Care, 2003;41(12):1343-1352

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Example of General Pretest to Select Best Measure of Patient Satisfaction

Compared 4 questionnaires on– Response rates, missing data, completion time,

patient ratings of the questionnaire 10 evaluation items at end of questionnaire

– Clarity of questions, ease of finding an answer, questions about unimportant issues, ease of completion, too long, layout confusing, lacked important questions

Perneger TV et al., A randomized trial of four patient satisfactionquestionnaires Med Care, 2003;41(12):1343-1352

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Problems with General Pretests

Respondents… often don’t understand the task. don’t want to appear as if they didn’t

understand have a hard time telling you anything was

wrong easier to say everything was fine

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In-Depth Cognitive Interviews

Derived from social and cognitive psychology to explore processes respondents use to answer survey questions

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Cognitive Interviews Examine 4 Steps in Answering Questions

Comprehend the question (as intended) Retrieve the information

– various strategies used to access memory Judgment formation - formulate an answer

– calculate or judge the correct information Edit response - decide what to report

– is answer embarrassing, socially undesirable?

Sudman S et al., Thinking About Answers, Jossey-Bass, San Francisco, 1996

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Purpose of Cognitive Interviews

To learn .. .. if respondents understand words and phrases

as intended (meaning) .. about the process of answering the questions .. whether items are unacceptable .. about the usefulness of response choices

– whether response choices are adequate

– how they use the response choices

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Two Types of Cognitive Interviews

Think aloud interviews– Respondent asked to think aloud as they

answer question Probe interviews

– Interviewer asks specific questions to elicit how respondent answered question

– Scripted and spontaneous probing

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Think Aloud Interviews

Thorough examination of the entire thought process of creating answers

Require that respondents verbalize their thought processes as they are answering items– Hard task for most people

Mostly done at “cognitive interviewing” labs, e.g., at National Institutes of Health

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Steps in Cognitive Interview Pretesting

Identify most problematic items and develop scripted “probes”

Decide on order of administration– Probes after each question or at the end

Recruit sample for cognitive interviews Administer entire questionnaire

– Administer probe questions Summarize results

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Probe Questions to Explore Meaning

What does the word _______ mean to you?

What does the phrase ________ mean to you?

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Example:Probing the Meaning of a Phrase

I asked you about how the office staff treated you personally ….

What does the phrase “office staff” mean to you?

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“the receptionist and the nurses”

“nurses and appointment people”

“the person who takes your blood pressure and the clerk in the front office”

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“the receptionist and the nurses”

“nurses and appointment people”

“the person who takes your blood pressure and the clerk in the front office”

We changed the question to receptionist and appointment staff

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Types of Probes (cont.)

Retrieval– How did you remember that?

Judgment– Why did you pick that number for your answer?

Response– Do you think that most people answer this

question honestly?Collins D. Quality of Life Research 2003. 12:229-38.

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Types of Probes (cont.) Redundancy

– How is the phrase “give you advice about your diet and exercise” different from the phrase “talk to you about your diet and exercise”?

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Types of Cognitive Probes (cont.)

Cultural appropriateness and meaning:– I asked you how often doctors asked you about

your health beliefs? What does the term ‘health beliefs’ mean to you?

“.. I don’t want medicine” “.. How I feel, if I was exercising…” “.. Like religion? --not believing in

going to doctors?”

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Types of Cognitive Probes (cont.)

Cultural appropriateness and meaning:– I asked you how often doctors asked you about

your health beliefs? What does the term ‘health beliefs’ mean to you?

“.. I don’t want medicine” “.. How I feel, if I was exercising…” “.. Like religion? --not believing in

going to doctors?” We changed the question to “personal beliefs

about your health”

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Overcoming “Social Desirability” in Cognitive Interviews

Ask respondents whether they think others…– would have difficulty answering a question

– would answer the question honestly

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Example of Probe on Difficulty: CES-D Item

“During the past week, how often have you felt that you could not shake off the blues, even with help from family and friends”

Probe: Do you feel this is a question that people would or would not have difficulty understanding?– Latinos more likely than other groups to report

people would have difficulty

TP Johnson, Health Survey Research Methods, 1996

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Example:Probing the Process of Answering

I asked you _____ and you answered____. – Why did you pick this answer?– What were you thinking of when you picked this

answer? – Can you tell me what you were thinking when

you answered this way?»Can you give me some examples?

What came to mind when I asked you _____?

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Example: Use of Response Scale

Do diverse groups use the response scale in similar ways?

Re questions about cultural competence of providers– Interviewers reported that Asian respondents

who were completely satisfied did not like to use the highest score on the rating scale

CPEHN Report, 2001

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Sample Result: Use of Response Scale

In an exercise class of Samoans, instructor asked them to rate the difficulty of the exercise he just did on a 1-10 scale

They did not understand what he meant by a 1-10 scale – “Western” metric?

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Cognitive Interviewing:Example of Probing Questions

Acceptability of Questions I asked you _____.

– Did you find this question offensive?

– Was it distressing to answer this question?

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Example of Probe for Acceptability

When I asked you how often you felt discriminated against by doctors because of your race or ethnicity, you answered (read answer given).– Were you offended by this question?

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Interviewer’s Role: Spontaneous Probing

Probe on items that appear to be problematic

If a long pause in answering..– “I noticed you pausing - what came to mind

when you I asked you that question?”

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Other Cues to Problems in Face-to- Face Pretests

When administering the survey… Be aware of behavioral cues related to

specific items or to questions in general– Discomfort

– Yawning

– Looking at their watch

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Two Approaches to Probing

Concurrent probing– Ask probes immediately after respondent has given

answer to survey item– Advantage-information is fresh in respondent’s

mind Retrospective probing

– Ask probes after entire interview– Advantage-able to assess standard administration of

items

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Special Script for Recruiting People for Cognitive Interviewing

Respondents often do not understand their role Explain to them how their help fits into the

larger study, goal of main study, process of creating questions

Explain their role clearly:

– “help us learn how to ask better questions”

– “help us make questions clearer for others”

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Recruiting Subjects for Cognitive Interviewing

Explain who you are, purpose of pretest, their role, expected duration (1-1.5 hours)– Subjects told it is a pretest and that their task is to

help by identifying problems Pay subjects since it is a special demand on

them (if you can) If survey is long, may have to pretest different

sections on different subjects Requires more total subjects

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Administer Questionnaire and Probes

Administer entire questionnaire– Or break into sections

Administer probes Audiotape entire interview including probes

– Transcribe audiotapes

RESULT: information on the entire process of administering the questionnaire

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Summarize Data on Pretest Interviews

Summarize problems and nature of problems for each item

Determine how important problems are Data become basis for possible

revisions/adaptations

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Behavioral Coding

Review transcripts to identify problems Two types of problems:

– Problems with standard administration of items» respondent and interviewer “problem” behaviors

– Problems identified with specific probe questions

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Examples of Behavioral Codes for Standard Administration

Interviewer behavior Hard to read - interviewer experiences

difficulty reading question

Respondent behavior Repeat question - respondent asks to have

the question repeated Asks for clarification

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Summarize Behavioral Coding For Each Item

Proportion of interviews with each problematic behavior

For standard administration– # of occurrences of each problem divided by N

» e.g., 7/48 respondents requested clarification For probes

– # of occurrences of each problem divided by N for probe

» e.g., 2/15 respondents did not understand meaning based on response to probe

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Behavioral Coding Summary Sheet: Standard Administration (N=20)

Item #

Interviewer: difficulty reading

Subject: asks to repeat Q

Subject: asks for

clarification

1 2/20 0 1/20

2 0 0 0

3 1/20 3/20 2/20

4 0 1/20 0

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Examples of Behavioral Codes Based on Probes

Probe on meaning – Open-ended responses indicate lack of

understanding Probe on use of response options

– Open-ended responses indicate response options are problematic

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I asked you how often doctors asked you about your health beliefs. What does the term “health beliefs” mean to you? “.. I don’t want medicine”

“.. How I feel, if I was exercising…” “.. Like religion? --not believing in

going to doctors?” Behavioral coding: Count number of times a subject

did NOT understand meaning as intended

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Behavioral Coding Summary Sheet: Standard Administration (N=20) + Probes

Item # ProbesMeaning unclear

Interviewer -difficulty

reading

Subject: asks to

repeat Q

Subject: asks for

clarification

1 10 2/10 2/20 0 1/20

2 0 0 0 0 0

3 15 4/15 1/20 3/20 2/20

4 15 0 0 1/20 0

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Summarize Behavioral Coding

Determine if problem is common– Items with only a few problems may be fine– Items are questionable when

» several types of problems were found» several subjects experienced the same problem

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Behavioral Coding Summary Sheet: Standard Administration (N=20) + Probes

Item # ProbesMeaning unclear

Interviewer -difficulty

reading

Subject: asks to

repeat Q

Subject: asks for

clarification

1 10 2/10 2/20 0 1/20

2 0 0 0 0 0

3 15 4/15 1/20 3/20 2/20

4 15 0 0 1/20 0

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Summarize Behavioral Coding (cont.)

Determine if common problems with an item are serious– Gross misunderstanding of the question– Yields completely erroneous answer– Couldn’t answer the question at all

Some less serious “common” problems can be addressed by improved instructions or a slight modification

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Now What!

Issues in adapting measures based on pretest results

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Options for Adapting or Revising

Depend on whether you are using a standard measure or a new measure

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Writing New Items

One approach to finding problems with a standard measure in diverse groups– Write some new items that you think will be better for

this group– Write them in the same format as the standard measure

Can test the adequacy of the original measure and a “modified” measure that includes your new items– A way to begin to develop new items

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Adapting Measures

If a measure needs modification in your opinion– Can contact author(s) to see if they would like to

work with you– Be sure your opinion is based on extensive pretests

in several groups by your group and/or other researchers

– Work with a measurement specialist to assure that your proposed modifications are likely to solve the problem

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Internal versus External Validity

Internal validity - your study is able to answer your research questions with a measure

External validity - your results on a measure can be compared to other studies using the same measure

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Tradeoffs of Using Adapted Measures

Modifying measures– Can improve internal validity - able to answer your

question with this measure – You lose external validity - can’t compare your scores

to other studies Can test measure in original and adapted

form– If “adapted” measure works better, use it

If “adapted” measure does not work better– Can still use original measure (it may not work either)

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Handouts: Examples of Probe Questions

Sample Cognitive Interview Protocol– Ron Hays and Leo Morales

Selected probes from Interpersonal Processes of Care study

Summary of NCHS working paper series on cognitive methods (website)

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Homework for Next Class (Dec 2)

Identify 4-5 questions in measure you have selected that might be a problem for your target population– Phrases, length, response choices

Write one “probe” question for each problem Conduct 2 pretests on persons similar to those

you are interested in Summarize briefly your results

Documents

1 Class 7 Pretesting measures and considerations in modifying or adapting measures November 10, 2005 Anita L. Stewart Institute for Health & Aging University