Maps have shown us how the events of this disastrous year have played out around the globe, from the Australian bushfires to the spread of the COVID-19 pandemic. But there are good reasons to question the maps we see.
Some of these reasons have been explored recently through maps of the bushfires or those created from satellite images.
Maps often inform our actions, but how do we know which ones are trustworthy? My research shows that answering this question may be critically important for the world’s most urgent challenge: the COVID-19 pandemic.
Why are trustworthy maps important?
Maps guide decisions, including those made by governments, private companies, and individual citizens. During the pandemic, government restrictions on activities to protect public health have been strongly informed by maps.
Governments rely on public cooperation with the restrictions, and they have used maps to explain the situation and build trust. If people don’t trust information from the government, they may be less likely to comply with the restrictions.
This highlights the importance of trustworthy COVID-19 maps. Maps can be untrustworthy when they don’t show the most relevant or timely information or because they show information in a misleading way.
Below are a few question you should ask yourself to work out whether you should trust a map you read.
What information is being mapped?
The number of cases of COVID-19 is an important piece of information. But that number could just reflect how many people are being tested. If you don’t know how much testing is being done, you can misjudge the level of risk.
Low case numbers might mean that there isn’t much testing being done. If the percentage of positive cases (positive test rate) is high, we might be missing cases. So not accounting for the number of tests can be misleading.
The World Health Organization suggests that at least ten negative tests to one positive test, a positive test rate of at most 10%, is the lowest rate of testing that is adequate.
In Australia, we have been at the forefront of making sure we are doing enough testing and we are confident that we are identifying most of the cases. Undertesting has been a problem in some other countries.
How is the information being mapped?
It’s not just the numbers that matter. How the numbers are shown is also important so that map readers get an accurate picture of what we know.
The Victorian Government recently advised Melburnians to avoid travel to and from several local council areas because of high case numbers. But their publicly available map does not show this clearly.
Compare the government-produced map with a map of the same data mapped differently. Most people interpret light as few cases and dark as more cases. The government-produced map uses dark colours for both low and high numbers of cases.