title: Variance estimation for population attributable risk in a complex cross-sectional animal health survey.
abstract: Population attributable risk estimates offer a method of combining information on population exposure and disease risk factors into a single measure. Univariate and multivariable methods exist for calculating point estimates and variances under the assumption of equal sampling probabilities. National Animal Health Monitoring System national studies typically use a complex survey design (where selection probabilities vary by design strata), which makes use of these methods of calculating variance inappropriate. We suggest the use of a method called "delete-a-group" jackknife to estimate the variance of population attributable risk when a complex survey design has been implemented. We demonstrate the method using an example of Johne's disease. Advantages of the "delete-a-group" jackknife method include simplicity of implementation and flexibility to estimate variance for any point estimate of interest.
authors.affiliation: US Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, Centers for Epidemiology and Animal Health, 555 S. Howes St, Fort Collins, CO 80521, USA. bruce.wagner@usda.gov
authors.forename: B A
authors.initials: BA
authors.lastname: Wagner
authors.forename: S J
authors.initials: SJ
authors.lastname: Wells
authors.forename: P S
authors.initials: PS
authors.lastname: Kott
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000517:prevention & control; D003430:Cross-Sectional Studies; D003612:Dairying / Q000706:statistics & numerical data; D006306:Health Surveys; D016015:Logistic Models; D010283:Paratuberculosis / Q000453:epidemiology* / Q000517:prevention & control; D011153:Population; D012307:Risk Factors; D014481:United States / Q000453:epidemiology