Wireless substitution: state-level estimates from the National Health Interview Survey, 2012.

OBJECTIVES: This report updates subnational estimates of the percentage of adults and children living in households that do not have a landline telephone but have at least one wireless telephone (i.e., wireless-only households). State-level estimates for 2012 are presented, along with estimates for selected U.S. counties and groups of counties, for other household telephone service use categories (e.g., those that had only landlines and those that had landlines yet received all or almost all calls on wireless telephones), and for one earlier 12-month period (July 2011-June 2012). METHODS: Small-area statistical modeling techniques were used to estimate the prevalence of adults and children living in households with various household telephone service types for 93 disjoint geographic areas that make up the United States. This modeling was based on 2007-2012 data from the National Health Interview Survey, 2006-2011 data from the American Community Survey, and auxiliary information on the number of listed telephone lines per capita in 2007-2012. RESULTS: The prevalence of wireless-only adults and children varied substantially across states. State-level estimates for 2012 ranged from 19.4% (New Jersey) to 52.3% (Idaho) of adults and from 20.6% (New Jersey) to 63.4% (Mississippi) of children.

Wireless substitution: state-level estimates from the National Health Interview Survey, 2010-2011.

OBJECTIVES: This report updates subnational estimates of the percentage of adults and children living in households without a landline telephone but with at least one wireless telephone (i.e., wireless-only households). State-level estimates for 2011 are presented, as well as estimates for selected U.S. counties and groups of counties, for other household telephone service use categories (e.g., those that had only landlines and those that had landlines yet received all or almost all calls on wireless telephones), and for two earlier 12-month periods (January-December 2010 and July 2010-June 2011). METHODS: Small-area statistical modeling techniques were used to estimate the prevalence of adults and children living in households with various household telephone service types for 93 disjoint geographic areas that make up the United States. This modeling was based on 2007-2011 data from the National Health Interview Survey, 2006-2010 data from the American Community Survey, and auxiliary information on the number of listed telephone lines per capita in 2007-2011. RESULTS: The prevalence of wireless-only adults and children varied substantially across states. State-level estimates for 2011 ranged from 15.3% (Rhode Island) to 44.6% (Idaho) of adults and from 15.2% (Rhode Island) to 58.6% (Mississippi) of children.

Wireless substitution: state-level estimates from the National Health Interview Survey, January 2007-June 2010.

OBJECTIVES: This report presents state-level estimates of the percentage of adults and children living in households that did not have a landline telephone but did have at least one wireless telephone. National estimates for the 12-month time period from July 2009 through June 2010 indicate that 23.9% of adults and 27.5% of children were living in these wireless-only households. Estimates are also presented for selected U.S. counties and groups of counties, for other household telephone service use categories (e.g., those that had only landlines and those that had landlines yet received all or almost all calls on wireless telephones), and for 12-month time periods since January-December 2007. METHODS: Small-area statistical modeling techniques were used to estimate the prevalence of adults and children living in households with various household telephone service types for 93 disjoint geographic areas that make up the entire United States. This modeling was based on January 2007-June 2010 data from the National Health Interview Survey, 2006-2009 data from the American Community Survey, and auxiliary information on the number of listed telephone lines per capita in 2007-2010. RESULTS: The prevalence of wireless-only adults and children varied substantially across states. State-level estimates for July 2009-June 2010 ranged from 12.8% (Rhode Island and New Jersey) to 35.2% (Arkansas) of adults and from 12.6% (Connecticut and New Jersey) to 46.2% (Arkansas) of children. For adults, the magnitude of the increase from 2007 to 2010 was lowest in New Jersey (7.2 percentage points) and highest in Arkansas (14.5 percentage points).

Reevaluating the need for concern regarding noncoverage bias in landline surveys.

OBJECTIVES: We used recent data to reexamine whether the exclusion of adults from households with no telephone or only wireless phones may bias estimates derived from health-related telephone surveys. METHODS: We calculated the difference between estimates for the full population of adults and estimates for adults with landline phones; data were from the 2007 National Health Interview Survey. RESULTS: When data from landline telephone surveys were weighted to match demographic characteristics of the full population, bias was generally less than 2 percentage points (range = 0.1-2.4). However, among young adults and low-income adults, we found greater bias (range = 1.7-5.9) for estimates of health insurance, smoking, binge drinking, influenza vaccination, and having a usual place for care. CONCLUSIONS: From 2004 to 2007, the potential for noncoverage bias increased. Bias can be reduced through weighting adjustments. Therefore, telephone surveys limited to landline households may still be appropriate for health surveys of all adults and for surveys of subpopulations regarding health status. However, for some behavioral risk factors and health care service use indicators, caution is warranted when using landline surveys to draw inferences about young or low-income adults.

Wireless substitution: state-level estimates from the National Health Interview Survey, January-December 2007.

OBJECTIVES: This report presents state-level estimates of the percentage of households that do not have a landline telephone, but do have at least one wireless telephone. These wireless-only households made up 14.7% of U.S. households in 2007. The report also presents state-level estimates of the percentage of adults living in wireless-only households. These wireless-only adults made up 13.6% of U.S. adults in 2007. METHODS: A two-sample modeling strategy was used to estimate the prevalence of wireless-only households and adults by state. This modeling was based on data from the 2007 National Health Interview Survey and the 2008 Current Population Survey's Annual and Social Economic Supplement. RESULTS: The results show that the prevalence of wireless-only households and adults in 2007 varied substantially across states. State-level estimates ranged from 5.1% (Vermont) to 26.2% (Oklahoma) of households and from 4.0% (Delaware) to 25.1% (Oklahoma) of adults. In addition, approximately one out of four adults (25.4%) living in the District of Columbia were wireless-only.

Telephone coverage and health survey estimates: evaluating the need for concern about wireless substitution.

OBJECTIVES: We sought to determine whether the exclusion of adults without landline telephones may bias estimates derived from health-related telephone surveys. METHODS: We took data from the 2004 and 2005 National Health Interview Survey and used logistic regression to compare the odds of behavioral risk factors and health care service use for adults with landline telephones to those for adults with only wireless telephones and adults without any telephone service. RESULTS: When interviewed, 7.2% of adults, including those who did and did not have wireless telephones, did not have landline telephones. Relative to adults with landline telephones, adults without landline telephones had greater odds of smoking and being uninsured, and they had lower odds of having diabetes, having a usual place for medical care, and having received an influenza vaccination in the past year. CONCLUSIONS: As people substitute wireless telephones for landline telephones, the percentage of adults without landline telephones has increased significantly but is still low, which minimizes the bias resulting from their exclusion from telephone surveys. Bias greater than 1 percentage point is expected only for estimates of health insurance, smoking, binge drinking, having a usual place for care, and receiving an influenza vaccination.

Estimating the prevalence of uninsured children: an evaluation of data from the National Survey of Children with Special Health Care Needs, 2001. Data evaluation and methods research.

UNLABELLED: The National Survey of Children with Special Health Care Needs revealed that 8.3% of children under 18 years of age were uninsured, a rate lower than the rate estimated by other national surveys. This report presents the results of an evaluation of the quality of this estimate, based on analyses of non-response, question design, interviewer and respondent effects, and the weighing and estimation process. National and State-level statistics on health insurance coverage for children with special health care needs (CSHCN) and for children without special needs are included in an appendix. SOURCE OF DATA: The National Survey of CSHCN is a survey module of the State and Local Area Integrated Telephone Survey. This survey of parents and guardians collected health insurance coverage information for a national sample of 215, 162 children. Data were collected from October 2000 through April 2002. RESULTS: Compared with other surveys, weighted data from the National Survey of CSHCN describe a population with a slightly larger proportion of Hispanic children and children from households with higher incomes. The National Survey of CSHCN was also the only survey to use a child-level design: A randomized experiment that varied the health insurance questions found that repeating the coverage questions for each child produced lower unisurance rates than household-level questions that first asked if anyone in the househol was insured. CONCLUSION: Question design differences explain much of the discrepancy between survey estimates of the uninsurance rate, but a definitive conclusion regarding the relative accuracy of the uninsurance rates is not possible.