one mobile phone = one person? - european commission · (2007). reaching the u.s. cell phone...
TRANSCRIPT
One mobile phone = One person?
Consequences of cell phone sharing for sampling and weighting in mobile phone surveys
Outline:
1. Background
1Darmstadt University of Technology | Institute of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
1. Background
2. Literature
3. Research questions
4. Methods
5. Results
6. Discussion
1. BackgroundOne mobile phone = one person?
Importance of cell phone studies for official statistics:
� telephone surveys as reliable, fast and cost-effective means for surveyseffective means for surveys
� already used for official statistics in Sweden, Estonia, Australia, Israel …
� rising mobile-only rates affect coverage
� mobile phone frame as supplement to landline telephone frame
2Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
1. BackgroundOne mobile phone = one person?
Current method:
� mobile phone = personal device
� no sampling equivalent to within household selection selection
� no use of design weight regarding several persons using one mobile phone
3Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
1. BackgroundOne mobile phone = one person?
Current calculation selection probability: (Gabler & Ayhan, 2007)
CC
FF m
km
k +•≈Π 1
→ Selection probability in cell phone frame depends only on number of cell phones the respondent owns
4Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
C
Ci
iF
Fii M
mk
zM
mk +•≈Π 1
1. BackgroundOne mobile phone = one person?
Is it legitimate to calculate the selection Is it legitimate to calculate the selection probability in cell phone frames based on
this assumption?
5Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
2. LiteratureOne mobile phone = one person?
�50 validation interviews, US (Brick et al., 2007a) → 33% sharing
�176 US mobile-only household screening interviews (Brick et al., 2007b) → 8%interviews (Brick et al., 2007b) → 8%sharing
� 6,952 interviews in the 2007 BRFSS study (Link et al., 2007) → 15% sharing
�700 interviews in a German cross sectional study (Häder & Häder, 2009) → 8% sharing
6Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
2. LiteratureOne mobile phone = one person?
Question wording as cause for differential rates:
�Question on household level
�Definition of “sharing”�Definition of “sharing”
�Sharing-questions might be perceived sensitive
�Focus on particular type of sharing only�Active vs. passive, hard vs. soft
7Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
2. LiteratureOne mobile phone = one person?
Passive sharing
�Other people answer
calls on respondent’s
mobile phonemobile phone
Active sharing
�Respondent answers
calls on other people‘s
mobile phone
8Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
3. Research questionsOne mobile phone = one person?
�What is the prevalence of sharing in the German mobile phone population?
�Is the sharing population different from the �Is the sharing population different from the general mobile phone population?
�How to develop a design weight regarding sharing behavior?
9Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
4. MethodsOne mobile phone = one person?
�2 recruitment studies from a Mobile Phone Panel in Germany 2009 (1); 2010 (2)
�Sampling with Gabler-Häder Design in mobile phone and landline frame (1); Mobile phone phone and landline frame (1); Mobile phone frame only (2)
�Sample size: n=1,452 (1); n=1,426 (2)
�Response Rate: ?+27% (1); 15% (2)
�Samples weighted for mobile-only proportion
10Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
5. ResultsOne mobile phone = one person?
Prevalence of active sharing:
Active Sharing 2009
Active Sharing 2010
Yes, always 12% (85) 7% (91)
11Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
Yes, most of the time
12% (87) 13% (178)
Yes, seldom 20% (140) 26% (365)
No, never 51% (358) 53% (731)
Only when requested
5% (34) 2% (27)
Total 100% (704) 100% (1,392)
5. ResultsOne mobile phone = one person?
Prevalence of passive sharing:
Passive Sharing 2009
Passive Sharing 2010
Yes, always 12% (81) 8% (107)
12Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
Yes, most of the time
12% (87) 13% (187)
Yes, seldom 18% (130) 24% (338)
No, never 48% (341) 54% (748)
Only when requested
2% (12) 1% (11)
Total 100% (652) 100% (1,392)
5. ResultsOne mobile phone = one person?
Sociodemographics of active sharers:
Active Sharer2009 (n=1,088)
Active Sharer 2010 (n=957)
Sex (male) .85 .96
Age (z) .73** .93
13Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
Age (z) .73** .93
Education (High school) .95 .87
Occupation (yes) .63** .87
Income (<2,001 Euro) .73+ .75
Marital status (married) 1.81** 2.28***
Household size (z) 1.15 1.18+
Nagelkerke`s R2 .061 .069
+ p < .1; * p < .05; ** p < .01
5. ResultsOne mobile phone = one person?
Sociodemographics of passive sharers:
Passive Sharer2009 (n=1,088)
Passive Sharer2010 (n=957)
Sex (male) .72* .82
Age (z) .95 .71**
14Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
Age (z) .95 .71**
Education (High school) .67* 1.08
Occupation (yes) .77 .69+
Income (<2,001 Euro) .80 .74
Marital status (married) 1.80** 2.12***
Household size (z) 1.30** 1.21
Nagelkerke`s R2 .081 .071
+ p < .1; * p < .05; ** p < .01
5. ResultsOne mobile phone = one person?
Active sharers are:
�Younger
�Less often employed
�Living in high-income households�Living in high-income households
�More often married
�Living in multi-person households
15Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
5. ResultsOne mobile phone = one person?
Passive sharers are:
�Female
�Younger
�Less educated�Less educated
�Less often employed
�More often married
�Living in multi-person households
16Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
6. DiscussionOne mobile phone = one person?
Developing a design weight regarding sharing:
�DWi = Design weight ∑ =
=h
j
i
z
DW
1
11
�h = # of mobile phone numbers that can be used to reach a respondent
�zij = # of eligible potential respondents for a particular mobile phone number
17Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
∑ =jijz1
6. DiscussionOne mobile phone = one person?
Developing a design weight regarding sharing:
Description of respondent(not necessarily owner of mobile
phone)
Design Weight
18Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
phone)
Owns 1 mobile phone, solely being used by himself
1.000
Owns 2 mobile phones, 1 being used alone, 1 being shared with spouse
0.667
Owns 2 mobile phones, both shared with one other person- takes calls on family cell phone
0.833
=
1
11
iDW
+=
2
1
1
11
iDW
++=
5
1
2
1
2
11
iDW
6. DiscussionOne mobile phone = one person?
Developing a design weight regarding sharing with information on:
�Equal usage of the mobile phone among sharing partners?sharing partners?
�Exact frequency of behavior
�Typical behavior of respondent when reached on another phone if incoming call asks for survey participation
19Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
6. DiscussionOne mobile phone = one person?
How to obtain this information?
�Assessment of introductory segment of mobile phone interview for indications of sharingsharing
�Respondent selection procedure: Random selection or asking for “owner” of mobile phone
�Necessary information in order to determine selection probabilities for each mobile phone owned by respondent
20Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
LiteratureOne mobile phone = One person?
Brick, J. M., Brick, P. D., Dipko, S., Presser, S., Tucker, C. & Yuan, Y. (2007a). Cell phone survey feasibility in the U.S.: Sampling and calling cell numbers versus landline numbers. Public Opinion Quarterly, 71 (1), 23 – 39.
Brick, J. M., Edwards, S. W. & Lee, S. (2007b). Sampling telephone numbers and adults, interview length, and weighting in the California Health Interview Survey Cell Phone Pilot Study. Public Opinion Quarterly, 71 (5), 793 – 813.
Gabler, S. & Ayhan, Ö. (2007). Gewichtung bei Erhebungen im Festnetz und Gabler, S. & Ayhan, Ö. (2007). Gewichtung bei Erhebungen im Festnetz und über Mobilfunk: Ein Dual Frame Ansatz. ZUMA Nachrichten Spezial 13: 39 – 46.
Häder, M. & Häder, S. (Eds.) (2009). Telefonbefragungen über das Mobilfunknetz. Wiesbaden: GWV
Link, M. W., Battaglia, M. P., Frankel, M., Osborn, L., & Mokdad, A. H. (2007). Reaching the U.S. cell phone generation. Comparison of cell phone survey results with an ongoing landline telephone survey. Public Opinion Quarterly, 71(5), 814-839.
Tucker, C., Brick, M. J. & Meekins, B. (2007). Household telephone service and usage patterns in the United States in 2004: Implications for telephone samples. Public Opinion Quarterly, 71 (1), 3 – 22.
21Darmstadt University of Technology | Institut fe of Sociology | Research Methods | Dipl.-Soz. Britta Busse & Prof. Dr. Marek Fuchs
Darmstadt University of TechnologyDepartment 02Institute of SociologyInstitute of SociologyResearch MethodsDipl.-Soz. Britta Busse
Residenzschloss S3|12 (Room 35/36)64283 Darmstadt
Tel.: +49 6151/16-64291Fax: +49 6151/16-72070
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