False positive rates and how this is associated to "case numbers"

You asked

Please provide the following information:

How are daily Covid-19 case numbers calculated in relation to:

How are false positives calculated and how is this number associated to "case numbers" for Covid-19?

Let's say 10,000 volunteers get tested for Covid-19.

What infection rate do you use?

What estimated, median false positive rate do you use?

Using your current methodology, from a sample of 10,000 volunteers, can you show me how many new cases would then be reported, showing how many false positives contribute to the overall new cases total.

We said

​Thank you for your request.

The results reported from the COVID-19 Infection Survey are directly from the test, and no test is perfect. There will be false-positives and false-negatives from the test, and false-negatives could also come from the fact that participants in this study are self-swabbing.

While we do not know the true sensitivity and specificity of the test because COVID-19 is a new virus, our data and related studies provide an indication of what these are likely to be. To understand the potential impact, we have estimated what prevalence would be in two scenarios using different possible test sensitivity and specificity rates.

You can find more information on these scenarios in our methodology article.