Monday, November 2, 2020

Covid-19 A very misleading map.

While going through some reports, I came across the following map showing the percentage change of 7-day (moving) average of confirmed new cases of Covid-19 from October 23 to October 30, 2020.

From the title 'Where Coronavirus is Surging around the World' this map is supposed to show people how bad or how good the situation of new covid-19 cases in a particular nation on October 30, 2020.

Judging by the colour, one may have the following conclusions:

1. Canada, US, Brazil China and Japan  are equally bad with 10% to 50% increase on October 30.

2. Russia performed better with only 0% to 10% increase in 7-day average.

3. India and Argentina are very good with 10% to 50% drop in 7-day average.

I don't know what is the intention of the person producing this map. But if this map is from the US and with the Presidential Election on November 3, possibly the message is to tell the American that the situation of Covid-19 in the US is not that bad. The US is as good as Canada, China and Japan.

But the moment one refer to the latest report (November 2) from the WHO, one would tend to wonder what is happening.

The US ranked No. 1 with 88,905 new cases and 522 new deaths on November 2. India is No. 2 with 37,592 new cases and 497 new deaths. Brazil is No. 3 with 8,501 new cases and 168 new deaths and Russia is No. 4 with 18,257 new cases and 238 new deaths. Argentina No. 7 with 9,598 new cases and 483ew deaths, whereas China (with a population of 1,439 million)  is ranked No. 56 with 24 new cases and zero new deaths, and Japan ( with a population of 126 million) ranked No.50 with 667 new cases and 8 new deaths.

The question is how can the US (88,905 new cases, 522 new death, population 331 million) and Brazil (8,501 new cases, 168 new death, population 213 million) be classified the same colour as China (24 new cases, zero death, population 1,439 million) and Japan (667 new cases, 8 new deaths, population 126 million) ???

How can Russia (18,257 new cases, 238 new deaths, population 145 million) be better than China and Japan ???

How can India that ranked No. 2 (37,592 new cases, 497 new deaths, population 1,384 million) and Argentina that ranked No. 7 (9,598 new cases, 483 new death, population 45 million) are very good with blue colour ???

The explanation:

Technically there is nothing wrong with the map but the way of preparing and presenting the map is questionable and the intention is also questionable.

1. The data used is 7-day (moving) average. Since the date mentioned in the map is from October 23 to October 30, I would assume that the comparison is between the 7-day average from October 23-29 (7 days) and the 7-day average from October 24-30 (7 days).

2. The number of new cases could be hovering around 80,000 for a population of 331 million (US) from October 23 to October 30 or it could be hovering around 24 cases for a population of 1,439 million (China), but as long as the percentage increase is 10% to 50%, on the above map, they are classified as the same. For example an increase of 10,000 new cases to the 80,000 cases is 12.5% and similarly an increase of 3 new cases to the 24 cases is also 12.5%, so the same. But can they really be the same category ???

3. Russia with yellow colour (0% to +10%) performed better than China with orange colour (+10% to +50%). But Russia with 18,000 new cases for a population of 145 million, with a 5% increase is 900 new cases. So its 7-day average increase from 18,000 new cases to 18,900 new case (5%) can be said to be better than China that has its 7-day average increase from 24 cases to 27 cases (12.5%) for a population of 1,439 million ???

4. India (ranked No. 2) and Argentina (ranked No. 7) performed very well with blue colour (-10% to -50%). But India with new cases at 37,592 with even a 20% drop, there are still 30,000 new cases. Argentina with 9,598 new cases with 20% drop, there are still 7,679 cases. Statistically based on the format of preparing the above map, these two countries performed much much better than China and Japan, but in actual fact are the covid-19 situation in these two countries really that good and better than China and Japan?

5. For example Solomon Island.


A country that has total cases increased from 8 to 13 with 5 new cases. assuming its 7-day average was 1 days and with a spike of 5 cases on the 8th day, its 7-day average will increase from 1 case to 1.57 cases, an increase of 57%. The colour code for this country will be red, blood red, and this country will be interpreted by the map at a glance as a country with covid-19 situation worst than the US, India, Russia, Brazil, etc but in WHO Covid-19 country ranking Solomon Islands is ranked No. 213 with total cases 13, new cases 5, total death at zero.

In conclusion, don't simply accept any statistical presentation of charts or maps. Technically the data used and the figures produced can be perfectly accurate and correct and statistically nothing wrong but the opinion presented can be twisted to suit the presenter's intended motive. Be careful.

No comments: