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Animal and Plant Health Inspection Service
U.S. Department of Agriculture
USDA FAQ's and resources about coronavirus (COVID-19).  LEARN MORE

Overview of Calculators & Tools

These calculators are intended to assist in developing the sampling plan section of an outbreak surveillance plan. In particular, these calculators are useful for estimating appropriate sample sizes (number of premises or number of animals) for the surveillance effort.

Tip: Use the output from the calculators as a guide for the sampling plan. Disease situations, veterinary knowledge, epidemiologic expertise, or other factors may indicate a need for sample sizes that are more or less conservative than the estimates provided from these calculators.

Premises Sample Size Calculator

This calculator uses an electronic spreadsheet (Excel) to assist the veterinary epidemiologist in estimating the minimum number of premises to sample regardless of the premises classification or the disease control area / zone where the premises is located.


Animal Sample Size Calculator

This calculator uses an electronic spreadsheet (Excel) to assist the veterinary epidemiologist in estimating the minimum number of animals to sample from a premises regardless of the disease control area / zone where the premises is located.


Sample Selection Calculators - Probability based

These two calculators use electronic spreadsheets (Excel) to assist the veterinary epidemiologist to choose the specific premises or animals to sample to meet the predetermined sample size.


Probability of Failure to Detect Diseased Animals

Sometimes resource limitations (e.g. money, personnel) or other factors may dictate a need to alter sample size estimates obtained from the Animal Sample Size Calculator or Premise Sample Size Calculator. This matrix uses an electronic spreadsheet (Excel) to assist the veterinary epidemiologist in estimating what the change in sample size means in terms of what the probability likely is of failing to detect diseased animals (or premises) that are present in the sample.





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