Pooled Prevalence Calculator This site has been developed with funding from the Australian Biosecurity Cooperative Research Centre for Emerging Infectious Disease. The site is intended for use primarily by participating CRC members and other researchers involved in estimating disease prevalence through structured surveys. The calculators provided here are particularly designed for estimating prevalence where samples are tested individually or in groups (pools) or where one or more tests are used with imperfect sensitivity and/or specificity. Site Contents Estimating individual prevalence from pooled samples: For fixed pool size and perfect test For fixed pool size and known test sensitivity and specificity For fixed pool size and uncertain test sensitivity and specificity For variable pool sizes and perfect test Bayesian estimation using a Gibbs sampler Users' comments I have been using some of your utilities on the web-site. This site is an absolute gold-mine!! Kristen Barfod, Department of Microbiological Food Safety, Danish Institute for Food and Veterinary Research. Estimating sample sizes required for prevalence estimation from pooled testing: For fixed pool size and perfect test For fixed pool size and uncertain test sensitivity and specificity Simulate sampling to assess the validity and precision of pooled testing strategies for estimating individual prevalence: For fixed pool size and perfect test For fixed pool size and known test sensitivity and specificity For fixed pool size and uncertain test sensitivity and specificity For variable pool sizes and perfect test Detection of disease or demonstration of freedom using pooled testing: Pooled testing for demonstration of freedom Bayesian methods to estimate prevalence from individual (unpooled) samples using imperfect test(s): For one test For two tests used concurrently Calculate parameters for prior probability distributions: Parameterise a single Beta probability distribution from mode and 5/95 percentiles Parameterise a single Beta probability distribution from count data Summarise Beta probability distributions for given alpha and beta parameters Estimate parameters for multiple Beta probability distributions or summarise distributions for specified parameters Additional information: About this site User guide (HTML) User guide (pdf format) Demonstration analyses Glossary Project Final Report (pdf format) References Links Acknowledgments

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This site was created by AusVet Animal Health Services with funding from the Australian Biosecurity Cooperative Research Centre. It provides a range of epidemiological tools for the use of researchers and epidemiologists, particularly in animal health. Please send any comments, questions or suggestions to Evan Sergeant Copyright © 2013 AusVet Animal Health Services