Over the past several decades, there has been a revolution in charting.
As data visualization became an ever larger part of business and media, bad charts have received more scrutiny and criticism. Data visualization expert Edward Tufte coined the term “chartjunk” in the 1980s to condemn the misleading distortions commonly found at the time. Statistician William Cleveland turned data visualization into a science by studying our cognition of different chart types. All of this attention on charts has led to a world with fewer lame pie charts and needlessly 3-D graphs.
The BJP, India’s ruling party, didn’t get the memo. This week, the party tweeted out one of most high-profile chart howlers in recent memory to its 10 million followers. The tweet was intended to defend the decision to hike petrol prices.
In this egregious use of a column chart, the column for September 2018 is shorter than in 2009 and 2014, even though petrol prices are much higher now than they were back then. An arrow points downward to the latest data point, highlight what is actually a positive change. Although the percentage rise in price between 2014 and 2018 is lower than in previous intervals, the other (upward) arrows illustrating those changes aren’t drawn according to any sort of coherent scale. As for the inscrutable expression of prime minister Narendra Modi, who is pictured at the scene of the chart crime, it’s hard to tell whether he’s proud or puzzled by the whole thing.
Anyway, an accurate version of the chart would look like this:
The opposition Congress party took the BJP’s ridiculous chart as an opportunity to take a shot at its rival. Congress tweeted out their own version of the chart, juxtaposed with international oil prices. It shows that Indian petrol prices mostly tracked the global price of crude upwards, until recently when the price petrol continued to rise despite a fall in the price of oil.
It’s hard to get away with junk charts these days, as the BJP now knows.