title: A field test of three LQAS designs to assess the prevalence of acute malnutrition.
abstract: BACKGROUND
  The conventional method for assessing the prevalence of Global Acute Malnutrition (GAM) in emergency settings is the 30 x 30 cluster-survey. This study describes alternative approaches: three Lot Quality Assurance Sampling (LQAS) designs to assess GAM. The LQAS designs were field-tested and their results compared with those from a 30 x 30 cluster-survey.
  
  
  METHODS
  Computer simulations confirmed that small clusters instead of a simple random sample could be used for LQAS assessments of GAM. Three LQAS designs were developed (33 x 6, 67 x 3, Sequential design) to assess GAM thresholds of 10, 15 and 20%. The designs were field-tested simultaneously with a 30 x 30 cluster-survey in Siraro, Ethiopia during June 2003. Using a nested study design, anthropometric, morbidity and vaccination data were collected on all children 6-59 months in sampled households. Hypothesis tests about GAM thresholds were conducted for each LQAS design. Point estimates were obtained for the 30 x 30 cluster-survey and the 33 x 6 and 67 x 3 LQAS designs.
  
  
  RESULTS
  Hypothesis tests showed GAM as <10% for the 33 x 6 design and GAM as > or =10% for the 67 x 3 and Sequential designs. Point estimates for the 33 x 6 and 67 x 3 designs were similar to those of the 30 x 30 cluster-survey for GAM (6.7%, CI = 3.2-10.2%; 8.2%, CI = 4.3-12.1%, 7.4%, CI = 4.8-9.9%) and all other indicators. The CIs for the LQAS designs were only slightly wider than the CIs for the 30 x 30 cluster-survey; yet the LQAS designs required substantially less time to administer.
  
  
  CONCLUSIONS
  The LQAS designs provide statistically appropriate alternatives to the more time-consuming 30 x 30 cluster-survey. However, additional field-testing is needed using independent samples rather than a nested study design.
authors.affiliation: Academy for Educational Development, FANTA Project, Washington DC 20009, USA. mdeitchl@aed.org
authors.forename: Megan
authors.initials: M
authors.lastname: Deitchler
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Valadez
authors.forename: Kari
authors.initials: K
authors.lastname: Egge
authors.forename: Soledad
authors.initials: S
authors.lastname: Fernandez
authors.forename: Mary
authors.initials: M
authors.lastname: Hennigan
mesh_terms: D000208:Acute Disease; D002648:Child; D016000:Cluster Analysis; D003198:Computer Simulation; D003906:Developing Countries; D005002:Ethiopia / Q000453:epidemiology; D006801:Humans; D044342:Malnutrition / Q000453:epidemiology*; D009749:Nutrition Surveys; D015995:Prevalence; D011785:Quality Assurance, Health Care / Q000379:methods*; D012107:Research Design; D012494:Sampling Studies; D013217:Starvation