The National Voices Project is conducted using GfK Custom Research, LLC web-enabled KnowledgePanel® and the KnowledgePanel Latino®, designed to be representative of the U.S. population. The KnowledgePanel® covers 97% of the U.S. population, including cell-phone-only households. For each survey, there are approximately 2000 respondents. Respondents working or volunteering on behalf of children are eligible to complete the survey.
To create the panel, a stratified random selection of telephone numbers and residential addresses is made, with greater numbers of addresses sampled in groups that have historically lower response rates. Persons in selected households are then invited by telephone or by mail to participate in the web-enabled KnowledgePanel®. To ensure that all households are able to participate in this panel, GfK Custom Research, LLC (GfK) provides a laptop and internet connection at no cost to those who agree to participate and who do not already have their own computers and internet access. People who already have computers and Internet service are permitted to participate using their own equipment. Panelists receive unique log-in information for accessing surveys online, and then are sent emails each month inviting them to participate in research.
For National Voices Project surveys, a unique KnowledgePanel® sample is drawn. The National Voices Project sample includes oversampling of African American and Hispanic panel members, to ensure adequate representation of these groups and to allow greater precision of estimates in analyses using these groups. This oversampling, as well as the oversampling at the panel level and the possibility of unequal nonresponse rates within various groups of interest, requires that analyses include complex survey sampling considerations to produce results that are generalizable to the national population.