Screening Inconsistency: A Problem with Multistage Screening for Rare PopulationsView Presentation
*Stephen J Blumberg, National Center for Health Statistics
Keywords: Screening, sampling, children with special health care needs, children with autism, children with intellectual disability
Conducting scientifically rigorous surveys of rare populations can be cost-prohibitive because obtaining a sufficient sample of eligible respondents via probability sampling requires a significant screening effort. It is possible to control costs through a multi-stage screening approach, but this methodology introduces the possibility that respondents' answers to the screening questions given at an initial stage may not match those given at a later stage. This screening inconsistency may mean that respondents who initially appear eligible no longer appear so later. The Survey of Pathways to Diagnosis and Services was intended to be a survey of parents of children with special health care needs (CSHCN) aged 6 to 17 years who were reported to have been told by a doctor or health care provider that the child had one of three selected development-related health conditions: autism spectrum disorder (ASD), developmental delay, or intellectual disability. These children were identified during the 2009-2010 National Survey of CSHCN (Time 1), and to the extent possible, their parents were recontacted for follow-up interviews (Time 2). Among children reported at Time 1 to have ever been diagnosed with ASD or intellectual disability, nearly one-in-ten were reported at Time 2 to have never been diagnosed with those conditions. Inconsistent screening was also noted among the group of children who were said to have once been diagnosed but, at Time 1, were said to not have the condition. Of these children, one-in-three ever diagnosed with ASD and three-in-four ever diagnosed with intellectual disability were reported at Time 2 to now have the condition. With this talk, we will take a careful look at this screening inconsistency problem. We will consider the impact of this inconsistency on defining the population of inference, determining its size, and making estimates of the characteristics of hard-to-reach populations.