Lies, Damned Lies, and Cartography
Here’s a terribly produced map from the Economist, from an article called ‘Feed the World: How hunger has changed across the developing world‘. In general, the information graphics that the Economist produces are excellent, but this one is baffling.
The data comes from a report on the ‘Global Hunger Index’ (GHI) from the International Food Policy Research Institute. According to the article: “The worst possible [GHI] score is 100, but in practice, anything over 25 is considered ‘alarming’. Scores under five, meanwhile, are indicative of ‘low hunger’.”
First, the map is title “Global hunger index 2010”, but only countries in the developing world are considered. Also, the text of the article acknowledges that the most-recent data is from before 2008, not 2010. (So, maybe it should have been titled “Global hunger index in the developing world” and then, underneath “Change from 1990-2007”, instead.)
The map shows the countries of the developing world, but they are not colored according to their GHI score. Instead, they are colored to show their change in GHI, in percentage terms, since 1990. So, a country that went from 20 to 30 (which is bad, both in absolute terms and in the direction of the change) is colored bright red.
Lighter shades of orange-red are also used on the map, but to indicate small or medium decreases in the GHI. Green means a large decrease in the GHI. So, both red and green indicate a decrease, but bright red means an increase.
To make things a little harder to understand, if the GHI was under 5 both in 1990 and 2010, then the change in the GHI is not worried about. Instead, the country is simply colored light green. That is, the color green is used both to indicate a change in GHI, but also (for some countries) to indicate its absolute level.
When using a color spectrum, it makes the most sense to me to have red indicate an increase in the GHI and shades of green represent decreases, with darker shades meaning larger decreases. If the country’s GHI is so low that its change is not an issue, then indicate that by using a color that is not part of the spectrum being used to indicate GHI changes (like blue, perhaps).
If all that wasn’t enough, one out of every 8 males is colorblind and can’t see the difference between most shades of red and green. (I don’t know what the demographics of The Economists readership is, but I’m suspecting it leans male.)
The text of the article doesn’t make the graphic any easier to comprehend. It ends by saying “Kuwait, Malaysia, Turkey and Mexico have been the most successful, cutting their scores by over 60%. Those where hunger has increased include North Korea, Comoros and Congo. Congo’s GHI score fell by over 60%, the worst of any country.”
Well, if decreases in the GHI are good, then why is the Congo’s drop of 60% considered “the worst of any country”?
I think the Economist should realize that this article is half-baked and have another go at bringing it up their normal standards.