Measuring Interviewer Effects on Survey Error

in SHARE

Annelies BlomJulie Korbmacher

Ulrich Krieger

Motivation

Korbmacher and Schröder (2010): consent to record linkage (SHARE wave 3)

„The decision making process is mainly influenced by the interview situation which in turn is driven by the interviewer-respondent-interaction ”

The role of the interviewer

…make contact …gain cooperation …ask survey questions …conduct measurements …record answers and measurements …maintain respondents’ motivation throughout

the interview

Standardized interviews to reduce variation in the entire data collection process

Types of interviewer effects in surveys

Interviewer

Measurement

Unit nonresponse

Contact Cooperation

Item nonresponse

Nonresponse- Error

Measurement- Error

Survey of Health, Ageing and Retirement in Europe (SHARE)

Multidisciplinary Micro data on health, socio-economic status,

social and family networks bi-annual, longitudinal (wave 1 in 2004) 20 European countries

SHARE-DE (Wave 4) specials: Record linkage (Pilot in wave 3) Collecting biomarkers Nonresponse experiment

Interviewer effects examined in SHARE Germany Wave 4

Interviewer

Income item nonresponse

Consent to biomarkers

blood pressure

height

waist circumference

dried blood spots

Unit nonresponse (incentives)

No unconditional incentive

10€ unconditional incentive

20€ unconditional incentive

40€ unconditional incentive

Consent to record linkage

Measuring and Explaining interviewer effects

Step 1: Measuring interviewer effects Step 2: Explaining interviewer effects

Who are the SHARE interviewers? Interviewer questionnaire

Underlying assumptions: Interviewers differentially impact on the data collection

process This differential impact is related to their – conscious

and subconscious – appearance and actions These actions can be explained by characteristics

collected in an interviewer survey

Interviewer survey

2011 Interviewer Training Wave 4 (trained 197

interviewers) Paper-and-pencil Voluntary and no incentives At the end of the training session Response rate: 83%

Link via InterviewerID to SHARE Survey data!

Conceptual framework

4 dimensions of interviewer characteristics

Unit non-response

Unit non-response (incentives)

Consent to biomarker collection

Consent to record linkage

Item nonresponse (income)

General attitudes

Own behavior

Experience with measurements

Expectations

5 aspects of SHARE Wave 4 (Germany)

Conceptual framework

General interviewer attitudes Reasons for being an interviewer Attitudes towards best practice Trust and data protection concerns

Interviewers‘ own behavior Interviewer as respondents Membership in social networks Income Blood donation Hypothetical questions:

disclose sensitive information consent to record linkage consent to biomarkers

Conceptual framework

Interviewers’ experience with measurements Conducting standardized interviews SHARE Conducting blood sugar tests

Interviewers’ expectations of unit response, consent and item response rates Expected response and consent rates:

Different incentive groupsBiomarker measurementsRecord linkage Income

Some results of the interviewer survey

Nonresponse

02

04

06

08

01

00

Expected unit response rates

no incentive 10 Euro20 Euro 40 Euro

Interviewers were confident that the higher the value of the incentive the more successful they would be in recruiting respondents.

• Interested in learning about the lives of other people

• Important to work on research that is relevant to society

expect higher RRs

expect lower RRs• Using of social networks (facebook)

Some results of the interviewer survey

Consent to record linkage Expected consent rate: 59,2%

Interviewers who would reveal personal information expect a significantly higher consent rate.

SSN Telephone number Private Address Address of health insurer

Some results of the interviewer survey

Interviewers who would consent to data linkage expect a significantly higher consent rate. Credit historyEmployment historyMedical recordsSocial benefits

Interviewer who are part of social networks expect significantly lower record linkage rates.

Outlook

Next steps: Completion of the survey Linking with SHARE survey data to learn more

about interviewer effects Can we explain interviewer effects in SHARE with

the interviewers’ characteristics allocated in the interviewer survey?