Statistics and Research: Coronavirus Disease (COVID-19)
by Max Roser, Hannah Ritchie, Esteban Ortiz-Ospina and Joe Hasell
Confirmed CoVid-19 deaths
1. What is the total number of confirmed deaths?
This chart shows the total confirmed deaths from COVID-19 over time. What is important to note about these death figures?
• the reported death figures on a given date does not necessarily show the number of new deaths on that day: this is due to delays in reporting;
• the actual death toll from COVID-19 is likely to be higher than the number of confirmed deaths – this is due to limited testing and problems in the attribution of the cause of death;
• how COVID-19 deaths are recorded may differ between countries (e.g. some countries may only count hospital deaths, whilst others have started to include deaths in homes).
2. Total confirmed deaths: how rapidly have they increased compared to other countries?
Charts which simply show the change in confirmed deaths over time are not very useful to answer the question of how the speed of the outbreak compares between different countries. This is because the outbreak of COVID-19 did not begin at the same time in all countries.
This chart here is designed to allow such comparisons.
The trajectory for each country begins on the day when that country had 5 confirmed deaths.
This allows you to compare how rapidly the number of confirmed deaths increased after the outbreak reached a similar stage in each country.
The grey lines in the background help you to see how rapidly the number of confirmed deaths is increasing.
These lines show the trajectories for doubling times of 1, 2, 3, 5, and 10 days. If the slope that a country is on is steeper than a particular grey line, then the doubling time of confirmed cases in that country is faster than that. For example, there are several countries for which the slope was steeper than the ‘…every 2 days’ line – this means their case count doubled faster than every two days.
3. What is the daily number of confirmed deaths?
The previous charts looked at the increase of total confirmed deaths – this chart shows the number of confirmed deaths per day.
Why is it helpful to also look at the three-day rolling average of daily confirmed deaths?
For all global data sources on the pandemic, daily data does not necessarily refer to deaths on that day – but to the deaths reported on that day.
Since reporting can vary very significantly from day to day – irrespectively of any actual variation of deaths – it is helpful to view the three-day rolling average of the daily figures. Above the chart you find the link to the rolling three-day average view.
→ We provide more detail in the section ‘Reported new cases on a particular day do not necessarily represent new cases on that day‘.
4. Daily confirmed deaths: are we bending the curve?
This trajectory chart shows whether countries make progress on bringing down the curve of new deaths.
To allow comparisons between countries the trajectory for each country begins on the day when that country first reported 5 daily deaths.
By default this chart is shown on a logarithmic vertical axis. We explain why in the next section. If you are not familiar with logarithmic axes we recommend you also look at this chart on a linear axis. The visual representation on these different axes can look very different.
5. Tests per case: how many tests to find one COVID-19 case?
This chart brings our data on testing together with the data on confirmed cases. The chart answers the question: How many tests did a country do to find one COVID-19 case?
• Some countries – for example Taiwan and Vietnam – did a large number of tests per each confirmed case.
• For others the ratio is more than two orders of magnitude lower.
These countries found a case for every few tests they did.
6. What is the total number of confirmed cases?
This chart shows the number of confirmed COVID-19 cases. What is important to note about these case figures?
• the reported case figures on a given date does not necessarily show the number of new cases on that day: this is due to delays in reporting;
• the actual number of cases is likely to be much higher than the number of confirmed cases – this is due to limited testing.
7. Total confirmed cases: how rapidly have they increased compared to other countries?
The trajectory for every country begins on the day when that country had 100 confirmed cases. This allows you to make comparisons of how quickly the number of confirmed cases has grown in different countries. Keep in mind that in countries that do very little testing the total number of cases can be much higher than the number of confirmed cases shown here.
8. What is the daily number of confirmed cases?
The previous charts looked at the increase of total confirmed cases – this chart shows the number of confirmed cases per day. Again you have the option to switch to the rolling three-day average via the link below the chart.
9. Confirmed cases: How did the total and daily number change over time?
The previous charts allowed you to compare countries. This is a chart that is helpful to understand the spread of the disease in a single country. In yellow you see the number of daily new confirmed cases and in red the total sum of confirmed cases.
10. World maps: Confirmed deaths relative to the size of the population
Why adjust for the size of the population?
It can be insightful to know not just how many have died compared to how many people actually live in that country.
For instance, if 1,000 people died in Iceland, out of a population of about 340,000, that would have a far bigger impact than the same number dying in the USA, with its population of 331 million.1 The death count in more populous countries tends to be higher – here you can see this correlation.
This is why the two maps below show the deaths per million people of each country’s population.