The increase of the number of tests and the increase in positive new cases in Austria. 22-10-20.

(This analysis may be useful for other countries, but the variation in the number of Tests and the corresponding Infection Rate must be calculated)

It has been said repeatedly that more positives occur because so many more tests are done.

But the increase in the number of exams is not the only cause. Another cause is the increase in the daily infection rate. There is not a lot of many more tests being done. There are quite a few more tests done.

Since 06-18-20, while the number of exams multiplied by approximately 4 (from 5 thousand to 20 thousand roughly), the daily Infection Rate increased approximately by 10 (from 1 to 10). Putting it in another way, while on 06-18 there was approximately 1 positive in every 100 examined, today approximately 10 in every 100 are detected.

More precision: on 06-18, 5,312 examinations were carried out and 38 positives were detected; rate of 0.72%. Yesterday 10-20-20, 19,469 examinations were made and 1,861 infected were detected; 9.56%.  In parallel to a 3.7-fold increase in examinations, there was a 13.3-fold increase in the infection rate.

 

If on 10-20 we had had the same infection rate as 06-18, there would have been 19,469 x 0.72 / 100 = 140 new positives yesterday and not 1,861.

 

The increase in the number of positives due to the increase in the number of examinations is 140 (hypothetical figure from yesterday) - 38 (infected from 06-18) = 102.

 

The rest of the increase in positives is due to the increase in the daily Infection Rate, that is, 1,861 - 140 = 1,721.

 

In other words, the increase in the number of tests was responsible for 6% of the increase in new positives, while the increase in the daily infection rate was responsible for 94%.

Data source:

https://www.sozialministerium.at/Informationen-zum-Coronavirus/Neuartiges-Coronavirus-(2019-nCov).html