

Calculate herd sensitivity (SeH) and herd specificity (SpH) for a
range of sample sizes and cutpoint numbers of reactors, for specified herd size,
test sensitivity, test specificity and design prevalence. Also calculates:
 SeH values where SpH is constrained to be greater than a specified minimum
value; and
 The sample size and cutpoint for maximum SeH given constraints of the range of
sample sizes and cutpoints and specified minimum SpH and maximum SeH.
Inputs include:
 Test sensitivity and specificity;
 Animallevel design prevalence (the hypothetical prevalence to be detected);
 Maximum desired SeH and minimum SpH;
 Specified herd/population size;
 Maximum and minimum sample sizes to be considered;
 Maximum and minimum cutpoint number of reactors to classify a herd/flock as positive;
 The desired precision of results (number of digits to be displayed after the decimal point); and
Results are calculated using the HerdPlus method (Greiner 2006?) and include:
 Tables and plots of SeH and SpH for combinations of sample size and cutpoints;
 A table of SeH values corresponding to SpH values greater than or equal to the
specified minimum SpH; and
 A summary of the sample size, cutpoint and maximised SeH given the specified constraints
on SeH and SpH.
Acknowledgement:Developed by Matthias Greiner and Evan Sergeant
