Use of multi-mode techniques in the National Children's Study two-tier high-low intensity recruitment strategy

The National Children's Study, the largest effort of its kind, is a longitudinal study of the effects of environment and genetics on child health, growth, and development. The current pilot phase, or “Vanguard Study,” seeks to inform the main study. The Vanguard Study assesses three recruitment strategies. This session focuses on the Two-Tier High-Low Intensity strategy, which uses a multi-mode approach to recruit and enroll women who are pregnant or trying to become pregnant; these women will form the initial birth cohort from which children will be enrolled. Using an address-based sampling frame, households are grouped into low-intensity and high-intensity segments, each being subject to lower or higher levels of contact and data collection. All households are screened for eligibility using low-intensity data collection efforts, an approach involving marketing, mail, telephone, and community outreach to encourage self-referral and enrollment. Enrolled women in low-intensity segments receive longitudinal follow-up via similar low-intensity methods while those in high-intensity segments are eligible for more intensive data collection, including in-person interviews, personal health care logs, and periodic follow-up via phone. Fathers are also eligible for an interview. The strategy's goals include: • Building rapport and encouraging self-referral through low-intensity efforts prior to engaging participants in more costly and intensive ways; • Developing information needed to better estimate bias between women who choose to participate in Low-Intensity and High-Intensity data collection. This session discusses implementation of the High-Low strategy in Los Angeles County, and examines the relative effectiveness of various methods based on interim evaluations.