NCS Advisory Committee, the NCS Program Office, Westat, the Vanguard Center principal investigators, and federal scientists.3 A review of this plan can be found in National Research Council (NRC) and Institute of Medicine (IOM) (2008). The current design uses a separate pilot (or “ Vanguard Study”) to assess quality of scientific output, logistics, and operations and a “Main Study” to examine exposure-outcome relationships. The house-to-house recruitment strategy endorsed with qualifications by the 2008 panel of the NRC/IOM was tested in the Vanguard sites, resulting in recruitment of fewer pregnant women and births than originally estimated. The issues associated with sampling were further studied in the additional Vanguard sites. As the results from Vanguard sites became available, there was much discussion about the most effective sampling approach among the NCS Program Office, federal and non-federal sampling experts, Vanguard principal investigators, and others. Considering this input, the NCS proposed the use of a multilayered cohort approach for the Main Study, which was one of the topics for discussion at the workshop that is the subject of this publication.
In the fall of 2012, NICHD requested that the Committee on National Statistics (CNSTAT) of the NRC and the IOM convene a joint workshop, to be led by CNSTAT. The statement of task was as follows:
An ad hoc steering committee will organize a public workshop on issues related to the overall design (including the sample design, participant recruitment, and framework for implementation) of the congressionally mandated National Children’s Study (NCS). The NCS is intended to follow a cohort of children identified at or before birth through age 21 years. The study consists of a pilot or Vanguard Study, currently under way, focused on the feasibility, acceptability, and cost of study implementation and logistics to run in advance of, and parallel to, a Main Study. Based on Vanguard Study experience to date, the National Institute of Child Health and Human Development (NICHD) is proposing a multilayered approach to enrollment, using a national probability sample of hospitals and birthing centers for a birth cohort, supplemented with additional cohorts of pregnant women and preconception women, as well as special samples of population groups that may be underrepresented in the main cohorts. NICHD will provide a background document on the proposed design that will be discussed by workshop participants. The committee will develop the agenda for the workshop, select and invite speakers and discussants, and moderate the discussion. Following the workshop, a designated rapporteur will prepare an individually authored summary of the presentations and discussion. NICHD will also be provided with a verbatim transcript of the event.
3The National Children’s Study has a website with a wealth of information concerning the history of the study and the activities that are under way. See http://www.nationalchildrensstudy.gov/Pages/default.aspx [June 2013].