As of 5 November 2021, 12pm, the Ministry of Health has detected a total of 1,767 new cases of COVID-19 infection, comprising 1,639 community cases, 120 dormitory resident cases and 8 imported cases. Amongst the community cases today are 284 seniors who are aged 60 years and above. The ratio of community cases for the past week over the week before is 0.81.

The fall in the number of cases today is likely due to fewer swabs being done over the Deepavali Public Holiday at Public Health Preparedness Clinics (PHPCs) and polyclinics. 

My observation 

The ratio is based on the number of cases for one week, compared to the previous week. Although there are less tests carried out on the public holiday, it should not affect the total number significantly.

There is another way to improve the measure. We can compare the test positive rate. 

For example, if there were 8,000 cases for the latest week and 10,000 cases for the previous week, the ratio is 0.8. 

If there were 80,000 tests carried out for the latest week and 100,000 tests for the previous week, the test positive rate is 10% for both weeks, so the growth rate is 1.0.

If the number of tests are the same for both weeks, the test positive rate is 8% and 10% respectively. The ratio remains at 0.8.

If the number of tests fluctuate significantly from one week to another, it is better to use the test positive rate to measure the ratio.

I hope that MOH has some statisticians that can help them to better interpret the data.

Tan Kin Lian