Do cell phone users differ by
frame and should we care?
Presenter
Michel Boudreaux
AAPOR, Phoenix, Arizona
May 13, 2011
Funded by a grant from the Robert Wood Johnson Foundation
Acknowledgments
• Funding support:
– MN Department of Human Services
– MN Department of Health
• Coauthors:
–
–
–
–
–
www.shadac.org
Kathleen Thiede Call
Donna McAlpine
Tim Beebe
Brett Fried
David Dutwin
2
National/Midwest Cell Phone Use
Adults Living in Wireless Only Households
30
26.6
Percent
25
24.9
20
15
10
14
US
Midwest
12.6
5
0
Jan-Jun 2007
www.shadac.org
Jan-Jun 2010
3
To screen or not to screen
• Lack of consensus in field on whether to:
1) Screen for cell phone only (CO) households
2) Include all but landline mostly
3) Interview the entire cell phone frame
• Excluding some cell users could introduce
error
• Including all users complicates weighting
due to overlapping probabilities of
selection
www.shadac.org
4
Research questions
• Are cases omitted when screening for CO
households different depending on which
frame they are captured in (LL vs. Cell)?
• Do these differences disappear when
controlling for post-stratification variables?
www.shadac.org
5
Data Sources
• 2009 MN Health Access Survey (MNHA)
– Ongoing survey of health insurance/access
– Accepted all cell phone completes
• 2010 MN Survey on Adult Substance Use
– Focus on prevalence of drug/alcohol use and
treatment patterns
– Accepted only CO and CM cases
www.shadac.org
6
Analysis
• T-test/pairwise comparisons of:
– Cell mostly sampled in LL versus Cell frame
• Regression models with telephone usage
as predictor, controlling for weighting
variables
• Full sample weights applied
www.shadac.org
7
Unadjusted Demographics, MNHA
Cell Mostly Users by Sample Frame
LL
90.4% 86.2%
2.3%
65+
www.shadac.org
Cell
87.1%
*
76.1%
26.3% 23.3%
*
5.3%
White
Home Owner
College
8
Unadjusted Health Insurance, MNHA
Cell Mostly Users by Sample Frame
LL
70.5%
Cell
*
57.0%
*
22.6%
15.%
5.6%
Public
www.shadac.org
Group
*
9.6%
Individual
8.8%
10.9%
Uninsured
9
Adjusted Health Insurance, MNHA
Adjusted Difference, LL vs Cell
0.15
0.00
0.04
-0.04
Uninsured
Public
Group
www.shadac.org
Individual
10
Unadjusted Demographics, MNSASU
Cell Mostly Users by Sample Frame
LL
Cell
89.6% 86.8%
45.5%
4.1%
4.1%
65+
www.shadac.org
*
37.7%
White
College
11
Unadjusted Health-Related Outcomes,
MNSASU
Cell Mostly Users by Sample Frame
LL
Cell
*
14.2%
9.6%
10.6%
9.0%
2.5%
Drug Use
www.shadac.org
Heavy Alcohol Use
2.4%
SMI
12
Adjusted Health-Related Outcomes,
MNSASU
Adjusted Mean Difference, LL vs. Cell
www.shadac.org
0.02
0.01
0.00
Drug Use
Heavy Alcohol Use
SMI
13
Discussion
• CM users from landline vs. cell frames do
differ on health outcomes
• However, post-stratification weighting
appears to correct for these differences
• This suggests that we can safely screen
for CO
• However, cost and variance remains an
issue
www.shadac.org
14
Contact information
• Michel Boudreaux
• State Health Access Data Assistance
Center (SHADAC)
– [email protected]
www.shadac.org
©2002-2009 Regents of the University of Minnesota. All rights reserved.
The University of Minnesota is an Equal Opportunity Employer
15