title: Multistage sampling for disease family registries.
abstract: BACKGROUND
  The objectives of a family-based disease registry range from characterizing measured genetic factors and gene-environment interaction effects to detecting novel susceptibility genes. Gathering complete information on exposure and disease status in all family members for a sample of affected subjects (probands) to address these diverse objectives would be prohibitively expensive.
  
  
  METHODS
  Multistage sampling can be used to design an efficient family-based disease registry. At each stage, the probands are classified on the basis of previously collected data, and a subsample is selected for more detailed observation. The design can be optimized to minimize the variance of any of the model parameter estimates, subject to a constraint on the total sample size.
  
  
  RESULTS
  We describe the basic statistical theory and its application to a four-stage sampling scheme proposed for the Cooperative Family Registry for Epidemiologic Studies of Colorectal Cancer at the University of Southern California.
authors.affiliation: Department of Preventive Medicine, University of Southern California, Los Angeles, CA 90089-9011, USA. kims@rcf.usc.edu
authors.forename: K D
authors.initials: KD
authors.lastname: Siegmund
authors.forename: A S
authors.initials: AS
authors.lastname: Whittemore
authors.forename: D C
authors.initials: DC
authors.lastname: Thomas
mesh_terms: D000483:Alleles; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D005190:Family; D006801:Humans; D012042:Registries; D012107:Research Design