The Impact of Wireless Substitution on Random-Digit-Dial Health Surveys
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Transcript of The Impact of Wireless Substitution on Random-Digit-Dial Health Surveys
The Impact of Wireless Substitution The Impact of Wireless Substitution on Random-Digit-Dial Health Surveyson Random-Digit-Dial Health Surveys
Centers for Disease Control and PreventionNational Center for Health Statistics
Stephen BlumbergStephen BlumbergJulian LukeJulian Luke
Goals of this PresentationGoals of this Presentation Describe the telephone coverage of the U.S. Describe the telephone coverage of the U.S.
household population, with a particular focus household population, with a particular focus on persons who have substituted wireless on persons who have substituted wireless telephones for landline telephonestelephones for landline telephones
Examine the potential bias that may result Examine the potential bias that may result when health surveys exclude households when health surveys exclude households without landline telephoneswithout landline telephones
National Health Interview SurveyNational Health Interview Survey In-person survey of the civilian In-person survey of the civilian
noninstitutionalized U.S. populationnoninstitutionalized U.S. population Annual household-level response rates are Annual household-level response rates are
very high (86-92%)very high (86-92%) Includes questions on residential telephone Includes questions on residential telephone
numbers to permit recontact of participantsnumbers to permit recontact of participants 2003: Added questions on working cellular 2003: Added questions on working cellular
telephonestelephones
Percentage of HouseholdsPercentage of HouseholdsWithout Landline TelephonesWithout Landline Telephones
0
4
8
12
16
20
1963 1970 1975 1980 1985-1986
1997 2001 Late2005
Identifying Wireless-Only PersonsIdentifying Wireless-Only Persons ““What is your family’s telephone number?”What is your family’s telephone number?” ““Does anyone in your family have a working Does anyone in your family have a working
cellular telephone?cellular telephone? ““Is ###-###-#### the telephone number for Is ###-###-#### the telephone number for
one of the cellular phones?”one of the cellular phones?” ““Is there at least one telephone inside your Is there at least one telephone inside your
home that is currently working and is not a home that is currently working and is not a cellular telephone?”cellular telephone?”
Prevalence of Adults and ChildrenPrevalence of Adults and ChildrenBy Household Telephone StatusBy Household Telephone Status
3.5
4.5
5.5
6.8
7.8
1.6 1.7 1.51.8 1.7
3.2
3.8
5.0
5.8
7.7
2.0 1.82.3
1.92.81.6
2.9
1.5
1.8
0
1
2
3
4
5
6
7
8
Jan – Jun2003
Jul – Dec2003
Jan – Jun2004
Jul – Dec2004
Jan – Jun2005
Jul – Dec2005
Per
cent
Adults Children
WirelessServiceOnly
NoTelephoneService
Prevalence of Adults and ChildrenPrevalence of Adults and ChildrenBy Household Telephone StatusBy Household Telephone Status During the second half of 2005During the second half of 2005
77% of nonlandline households had wireless 77% of nonlandline households had wireless telephonestelephones
17.1 million adults (18+) were wireless-only17.1 million adults (18+) were wireless-only 5.7 million children (<18) were wireless-only5.7 million children (<18) were wireless-only
Growth since 2003Growth since 2003 23% compound growth in the prevalence of 23% compound growth in the prevalence of
wireless-only adults EVERY SIX MONTHSwireless-only adults EVERY SIX MONTHS 19% compound growth in the prevalence of 19% compound growth in the prevalence of
wireless-only children EVERY SIX MONTHSwireless-only children EVERY SIX MONTHS But a jump of 33% in the past six months!!But a jump of 33% in the past six months!!
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Home Ownership Statusby Home Ownership Status
3.9% of adults 3.9% of adults owning or buying owning or buying homehome
8.5% of adults with 8.5% of adults with other arrangementsother arrangements
19.6% of adults 19.6% of adults renting their homerenting their home
02468
101214161820
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Household Structureby Household Structure
34.0% of adults 34.0% of adults living with living with roommatesroommates
12.4% of adults 12.4% of adults living aloneliving alone7.1% of adults 7.1% of adults living with children living with children
0
5
10
15
20
25
30
35
40
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
6.0% of adults living 6.0% of adults living with related adults with related adults
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Ageby Age
17.8% of 18-2417.8% of 18-24
10.7% of 25-4410.7% of 25-44
3.7% of 45-64 3.7% of 45-64
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
1.2% of 65+ 1.2% of 65+
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Sexby Sex
8.6% of men8.6% of men7.0% of women 7.0% of women
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Race/Ethnicityby Race/Ethnicity
11.3% of Hispanic 11.3% of Hispanic adultsadults8.6% of Black 8.6% of Black nonHispanic adultsnonHispanic adults7.0% of White 7.0% of White nonHispanic adults nonHispanic adults
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Household Poverty Statusby Household Poverty Status
14.3% of adults in 14.3% of adults in povertypoverty12.8% of adults 12.8% of adults near povertynear poverty
7.0% of higher 7.0% of higher income adults income adults
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Highest Completed Educationby Highest Completed Education
8.8% of adults with 8.8% of adults with less than HSless than HS
9.5% of adults with 9.5% of adults with some collegesome college
7.7% of high 7.7% of high school graduates school graduates
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
6.3% of college 6.3% of college graduates graduates
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Employment Status Last Weekby Employment Status Last Week
9.2% of adults 9.2% of adults working at a jobworking at a job
15.5% of adults 15.5% of adults going to schoolgoing to school
6.2% of adults 6.2% of adults keeping house keeping house
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
3.8% of other 3.8% of other adults adults (incl. unemployed)(incl. unemployed)
Prevalence of Wireless-Only Adults byPrevalence of Wireless-Only Adults byMetropolitan Statistical Area StatusMetropolitan Statistical Area Status
8.8% of adults in 8.8% of adults in MSAsMSAs5.1% of adults 5.1% of adults not in MSAs not in MSAs
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
Prevalence of Wireless-Only AdultsPrevalence of Wireless-Only Adultsby Geographic Regionby Geographic Region
4.7% in Northeast4.7% in Northeast
9.6% in South9.6% in South8.8% in Midwest 8.8% in Midwest
0
2
4
6
8
10
12
14
16
18
Jan 2003 –Jun 2003
Jul 2003 –Dec 2003
Jan 2004 –Jun 2004
Jul 2004 –Dec 2004
Jan 2005 –Jun 2005
Jul 2005 –Dec 2005
6.3% in West6.3% in West
Multivariate Analyses: SEARCHMultivariate Analyses: SEARCH Sequential series of chi-square analyses to Sequential series of chi-square analyses to
identify the predictor variables that yield the identify the predictor variables that yield the greatest differences in the distributions of greatest differences in the distributions of the dependent variablethe dependent variable Predicting “landline absent” vs. “landline Predicting “landline absent” vs. “landline
present”present”
Prevalence of Adults Living in Prevalence of Adults Living in Households Without Landlines, 2005Households Without Landlines, 2005
All Adults9.0%
Owns Home4.2%
Rents Home22.2%
Age 37+2.6%
Age 18-368.1%
Married /Widowed
1.8%
Div / Sep /Never Married
6.5%
Age 31+14.7%
Age 18-3033.1%
Householdsize > 225.4%
Household size = 1 or 2
41.5%
Householdsize > 2
5.2%
Household size = 1 or 2
17.8%
Married /Widowed
9.2%
Div / Sep /Never Married
20.7%
Coverage BiasCoverage Bias Two factors determine the degree of Two factors determine the degree of
coverage bias due to telephone ownership coverage bias due to telephone ownership in a telephone survey:in a telephone survey: The percentage of persons without landline The percentage of persons without landline
telephones in the population of interesttelephones in the population of interest The magnitude of the difference between The magnitude of the difference between
persons with and without landline telephones on persons with and without landline telephones on the variable of interestthe variable of interest
Health Characteristics ExaminedHealth Characteristics Examined Health-related behaviorsHealth-related behaviors
5+ alcoholic drinks in one day (past year)
Smoking (current) Leisure-time physical
activity (regularly) Health statusHealth status
Excellent or very good health status
Serious psychological distress (past 30 days)
Obesity Asthma episode (past
year) Diabetes (ever diagnosed)
Health care service useHealth care service use Has a usual place to go
for medical care Received influenza
vaccine (past year) Received pneumococcal
vaccine (ever) Tested for HIV (ever) Financial barrier to
needed care (past year) Uninsured (current)
For these 14 estimates,For these 14 estimates, weighted data fromweighted data from
January – December 2005January – December 2005were produced by thewere produced by the
NHIS Early Release Program.NHIS Early Release Program.
Percent of Adults with Various Health Percent of Adults with Various Health Characteristics, by Phone StatusCharacteristics, by Phone Status
Has a Has a landline landline
telephonetelephone
Wireless-Wireless-onlyonly
No No telephonetelephone
5+ alcoholic drinks in 1 day5+ alcoholic drinks in 1 day 17.917.9 38.238.2 19.219.2Current smokerCurrent smoker 19.419.4 33.333.3 36.836.8Psychological distressPsychological distress 2.82.8 3.53.5 7.87.8Ever diagnosed with diabetesEver diagnosed with diabetes 7.87.8 3.43.4 7.37.3Health excellent / very goodHealth excellent / very good 61.261.2 68.068.0 47.447.4Regular physical activityRegular physical activity 29.929.9 36.436.4 21.021.0
Percent of Adults with Various Health Percent of Adults with Various Health Characteristics, by Phone StatusCharacteristics, by Phone Status
Has a Has a landline landline
telephonetelephone
Wireless-Wireless-onlyonly
No No telephonetelephone
Uninsured (when interviewed)Uninsured (when interviewed) 14.314.3 31.531.5 40.440.4Financial barriers to careFinancial barriers to care 6.46.4 12.912.9 14.614.6Has a usual place for careHas a usual place for care 86.486.4 66.966.9 67.467.4Flu vaccinationFlu vaccination 22.422.4 9.59.5 16.516.5Pneumococcal vaccinationPneumococcal vaccination 17.517.5 7.67.6 9.29.2Ever tested for HIVEver tested for HIV 34.234.2 46.246.2 40.040.0
Potential Bias in Prevalence EstimatesPotential Bias in Prevalence Estimatesfor All Adultsfor All Adults
““RDD” RDD” (Landline (Landline phones)phones)
In-Person In-Person (All (All
Adults)Adults)
5+ alcoholic drinks in 1 day5+ alcoholic drinks in 1 day 17.917.9 19.619.6Current smokerCurrent smoker 19.419.4 20.920.9Has a usual place for careHas a usual place for care 86.486.4 84.584.5Flu vaccination in past yearFlu vaccination in past year 22.422.4 21.221.2Ever tested for HIVEver tested for HIV 34.234.2 35.335.3Uninsured (when interviewed)Uninsured (when interviewed) 14.314.3 16.216.2
These were the only differences (of These were the only differences (of the 14 measures considered) that are the 14 measures considered) that are greater than one percentage point.greater than one percentage point.
Wireless-Only: A SummaryWireless-Only: A Summary In late 2005, 10.4% of all households did not In late 2005, 10.4% of all households did not
have a landline telephone and could not be have a landline telephone and could not be reached by random-digit-dial telephone reached by random-digit-dial telephone surveyssurveys
Rate is growing by approximately one Rate is growing by approximately one percentage point every 6 monthspercentage point every 6 months
Noncoverage of wireless-only households in Noncoverage of wireless-only households in telephone surveys can lead to bias, but the telephone surveys can lead to bias, but the magnitude of that bias is still smallmagnitude of that bias is still small
American Journal of Public HealthAmerican Journal of Public Health,,May 2006, vol. 96, pp. 926-931May 2006, vol. 96, pp. 926-931
For More Information…For More Information… Stephen BlumbergStephen Blumberg
Centers for Disease Control and PreventionCenters for Disease Control and PreventionNational Center for Health StatisticsNational Center for Health Statistics3311 Toledo Road, Room 21123311 Toledo Road, Room 2112Hyattsville, Maryland 20782Hyattsville, Maryland 20782
[email protected]@cdc.gov