Survey methodology

The 2000 Iowa Child and Family Household Health Survey was a telephone interview conducted with a stratified random sample of 3200 families with children in Iowa. The interview included approximately 125 questions, depending on the number of questions relevant to the family being interviewed. The survey instrument was developed by the research team after evaluating many existing survey instruments such as the National Survey of American Families (NSAF) and the National Health Interview Survey (NHIS).[1,2] The screening instrument developed by the Foundation for Accountability (FACCT) was used to identify CSHCN.[3]

Calls to identify families with children in Iowa were begun using a random list of phone numbers provided by a private vendor. To allow for regional comparisons, 400 interviews were completed in each of eight regions of the state. All regions consisted of multiple counties except for Polk and Scott counties, which were each considered their own region. The design of this study yielded a representative sample of families with children in Iowa.

The survey process began with a screening question to determine if the residence was home to a family with children. If so, the adult most knowledgeable about the health and health care of a randomly selected child under age 18 in the household was asked to complete the interview.

The dispositions of calls made to complete the 3200 interviews were as follows:

Table 1. Participation Rate for 2000 Iowa Child and Family Household Health Survey
Number completing the interview
3241
Number of refusals or unable to complete interview
1349
Participation Rate
71%

To make statewide estimates by age categories, the survey results were weighted and post-stratified using the county-level 2000 US Census data.4 The telephone interviews were conducted between May and October 2000 by the Center for Social and Behavioral Research at the University of Northern Iowa. The University of Northern Iowa Human Subjects review board approved the protocol regarding the telephone interview portion of this study.

In any telephone-based survey, there is a possibility that results may be biased because those without telephones are not interviewed, and they may have different health conditions and health care needs than those with telephones. In Iowa, it is estimated that three percent of households do not have telephones.5


1 http://newfederalism.urban.org/nsaf/
2 http://www.cdc.gov/nchs/nhis.htm
3 http://www.facct.org/
4 http://factfinder.census.gov/home/en/sf1.html
5 Anonymous, 200 "Telephone Information by State." Survey Sampling, Inc., One Post Road, Fairfield, CT 06430