This program calculates the approximate numbers of pools required for given values for pool
size, estimated prevalence and desired confidence and precision of the estimate, assuming fixed pool sizes and a
test with uncertain estimates for sensitivity and specificity. See the User Guide
for more details. See demonstration analysis
For this option it is not possible to calculate an optimum value for m that minimises
the variance of the estimated prevalence (see Sample size for
fixed pool size and perfect tests ). Therefore, final selection of pool size and corresponding number
of pools is a compromise between pool size and number of pools. To minimise bias, it is better
to have more pools of a smaller size, rather than fewer, larger pools.
Required inputs are the estimated true prevalence, the desired level of precision (or acceptable
error) and the desired level of confidence. You also need to enter point estimates of test
sensitivity and specificity and the sample sizes used to calculate these estimates. For
example, you might wish to estimate the prevalence
where the true value is assumed to be about 0.01 (1%), and you wish to have 95% (0.95) confidence
that the true value is within +/- 0.005 (0.5%) of your estimate, with a test that has a sensitivity
of 0.9 (90%) and specificity of 0.99 (99%) and where sensitivity and specificity were estimated
using sample sizes of 100 and 1000 respectively. You can also input a suggested pool size if desired,
and the program will calculate the corresponding number of pools to be tested for
that pool size (in addition to predetermined pool sizes). Suggested pool size is ignored if it is zero.
The program calculates the number of pools required for the input-scenario for a range of pool sizes
and presents the results in tabular and graphical formats. Results where the recommended number of pools is less
than 2 are ignored.