Simulate sampling for variable pool sizes

Input Values

Introduction

This utility simulates sampling and prevalence estimation for up to 6 different pooling strategies for and up to 5 different pool sizes for each strategy. Simulations assume perfect test sensitivity and specificity and the specified assumed prevalence in the population. The program runs multiple iterations of sampling and estimation and calculates the mean prevalence and confidence limits for the specified level of confidence across all iterations and estimates the level of bias in the prevalence estimates. See the User Guide for more details. See demonstration analysis

The program uses a generalised linear model to estimate prevalence and confidence limits for variable pool sizes and compares the mean estimates to the assumed (design) prtevalence to estimate bias. The program assumes that the test used has perfect sensitivity and specificity but allows for the estimates of sensitivity and specificity to be incorrect, allowing assessment of the potential impact of inaccurate estimates on the resulting prevalence estimate.

Inputs

Required inputs for this program are:

  • assumed true prevalence of infection - between 0 and 1;
  • true test sensitivity and specificity - between 0 and 1;
  • the desired level of confidence - between 0 and 1;
  • the number of iterations to simulate - a positive integer; and
  • the size and number of pools to be tested for each strategy to be simulated. This data should be copied and pasted from a spreadsheet format as described below.

Outputs

Outputs are summarised across all iterations for each strategy entered and presented in a summary table. The main outputs are:

In addition, detailed results for all iterations for each strategy can be downloaded as a text file, and histograms of the prevalence estimates can be viewed by clicking on the appropriate icons in the summary results table.

Note:

Data for pool sizes and associated numbers of pools tested should be pasted into the data submission area. You can enter any number of strategies to simulate, with a new row required for each strategy. You must enter at least three columns of data, labeled "Strategy", "PoolSize" and "Pools". Where there are multiple pool sizes for a strategy enter each pool size and corresponding number of pools on a new row. Include a header row containing the names.

This analysis may take several minutes to complete, depending on the number of strategies and the number of iterations required.

Design parameters:
Assumed true prevalence:
True test sensitivity:
True test specificity:
Desired Confidence level:
Simulation details:
Number of iterations:

Data:

This module takes several minutes to run, depending on numbers of scenarios and iterations requested so that your web browser could time-out. If you have problems, enter your email address and an email will be sent to you with a link to the results.

Paste data in the space below. Data columns can be in any order but must include columns labeled "Strategy", "Poolsize" and "Pools". A header row specifying column names must also be included.
Download example data


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