title: The impact of complex survey design on prevalence estimates of intakes of food groups in the Australian National Children's Nutrition and Physical Activity Survey.
abstract: OBJECTIVE
  To assess the impact of the complex survey design used in the 2007 Australian National Children's Nutrition and Physical Activity Survey (ANCNPAS07) on prevalence estimates for intakes of groups of foods in the population of children.
  
  
  METHODS
  The impacts on prevalence estimates were determined by calculating design effects for values for food group consumption. The implications of ignoring elements of the sample design including stratification, clustering and weighting are discussed.
  
  
  METHODS
  The ANCNPAS07 used a complex sample design involving stratification, a high degree of clustering and estimation weights.
  
  
  METHODS
  Australian children aged 2-16 years.
  
  
  RESULTS
  Design effects ranging from <1 to 5 were found for the values of mean consumption and proportion of the population consuming the food groups. When survey weights were ignored, prevalence estimates were also biased.
  
  
  CONCLUSIONS
  Ignoring the complex survey design used in the ANCNPAS07 could result in underestimating the width of confidence intervals, higher mean square errors and biased estimators. The magnitude of these effects depends on both the parameter under consideration and the chosen estimator.
authors.affiliation: Centre for Statistical and Survey Methodology, University of Wollongong, Northfields Avenue, Wollongong, New South Wales 2522, Australia. sburden@uow.edu.au
authors.forename: Sandy
authors.initials: S
authors.lastname: Burden
authors.forename: Yasmine
authors.initials: Y
authors.lastname: Probst
authors.forename: David
authors.initials: D
authors.lastname: Steel
authors.forename: Linda
authors.initials: L
authors.lastname: Tapsell
mesh_terms: D000293:Adolescent; D001315:Australia; D001835:Body Weight; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D002675:Child, Preschool; D016000:Cluster Analysis; D002149:Energy Intake; D005247:Feeding Behavior; D006801:Humans; D009043:Motor Activity; D009749:Nutrition Surveys