0990-PSUNC-TrackingSurvey-Knowledge Networks Panel Recruitment Methodology

Knowledge Networks Panel Recruitment Methodology

Participants in the Knowledge Networks panel are first selected using list-assisted random-digit-dialing (RDD) telephone methodology, providing a probability-based starting sample of U.S. telephone households. The panel sample is then adjusted to match U.S. Census demographic benchmarks to reduce error due to non-coverage of non-telephone households and to reduce bias due to non-response and other non-sampling errors. Knowledge Networks excludes only those banks of telephone numbers (consisting of 100 telephone numbers) that have zero directory- listed phone numbers. Knowledge Networks’ telephone numbers are selected from the 1 or more banks with equal probability of selection for each number. The sampling is done without replacement to ensure that numbers already fielded by Knowledge Networks do not get fielded again. Having generated the initial list of telephone numbers, the sample preparation system excludes confirmed disconnected and non-residential telephone numbers. Next, the sample is screened to exclude numbers that are not in the WebTV Internet Service Provider network. This process results in the exclusion of approximately 6% to 8% of the United States population. This percentage is diminishing steadily, and as of July 2001, Knowledge Networks will begin to include a small sample from out of the WebTV Internet Service Provider network in the panel to represent these areas and reduce coverage error. The sample frame is updated quarterly. Telephone numbers for which Knowledge Networks is able to recover a valid postal address (about 50%) are sent an advance mailing informing them that they have been selected to participate in the Knowledge Networks Panel. In addition to information about the Knowledge Networks Panel, the advance mailing also contains a monetary incentive to encourage cooperation when the interviewer calls. Following the mailing, the telephone recruitment

process begins. The numbers called by experienced interviewers consist of all numbers sent an advance mailing, as well as 50% of the numbers not sent an advance mailing. The resulting cost efficiency more than offsets the decrease in precision caused by the need for sample weights. Cases sent to telephone interviewers are dialed up to 90 days, with at least 15 dial attempts on cases where no one answers the phone, and 25 dial attempts on phone numbers known to be associated with households. Extensive refusal conversion is also performed. An interview, which typically requires about 10 minutes, begins with the interviewer informing the household member that they have been selected to join the Knowledge Networks Panel. Household members are told that in return for completing a short survey weekly, the household will be given a WebTV set-top box and free monthly Internet access. All members in the household are then enumerated, and some initial demographic variables and background information of prior computer and Internet usage are collected. Once participants are recruited into the panel, they can be contacted by e-mail (instead of by phone or mail) to participate in any number of studies.

Households already having Internet access are permitted to use their own Internet-connected computers for self-administration of interviews. In contrast, each non-Internet household is provided with identical hardware for survey administration. Microsoft’s WebTV is the hardware platform currently used by the Knowledge Networks panel. The device consists of a set-top box that connects to a TV and the telephone. It also includes a remote keyboard and pointing device. WebTV has a built-in 56K modem that provides the household with a connection to the Internet. The base unit also has a small hard drive to accommodate large file downloads, including video files. File downloads do not require any user intervention and usually occur during off hours. Prior to shipment, each unit is custom configured with individual e-mail accounts, so that it is ready for immediate use by the household. Most households are able to install the hardware without additional assistance, though Knowledge Networks maintains a telephone technical support line and will, when needed, provide on-site installation. The Knowledge Networks Call Center also contacts household members who do not respond to e-mail and attempts to restore contact and cooperation.

All new panel members are sent an initial survey to confirm equipment installation and familiarize them with the WebTV unit. Demographics such as gender, age, race, income, and education are collected for each participant to create a member profile. This information can be used to determine eligibility for specific studies and need not be gathered with each survey. Starting in August 2002, Knowledge Networks began oversampling households that have pre-existing, home-based Internet access, allowing these households to participate in the Web-enabled panel using their own equipment and Internet access. These panel members are enrolled into a panel loyalty program intended to encourage long-term participation in the research panel. The above Knowledge Network’s procedures are in place prior to this information collection and are not part of the public burden associated with this collection. This approach also reduces burden placed on participants, since e-mail notification is less obtrusive than telephone calls, and most respondents find answering Internet questionnaires to be more interesting and engaging than being questioned by a telephone interviewer.