Criticising charts

I missed this one: in October, Dutch economics journal ESB published an article that critically reviews all the charts in a report of the CPB (the semi-offical neoliberal economic institute that dominates Dutch policy debates). Authors Frank Kalshoven and Peter van Bergeijk find that on average, as many as four out of eight aspects of the charts have been done badly.

The authors invented a scale to assess charts, using the following criteria: the title describes what the chart shows; abbreviations and terms are explained; axis units are clearly described; axes are aligned; the source is explicitly mentioned; charts tell a clear story; charts contain little «noise» and there’s an explicit relation between panels in a chart.

One of the charts discussed is the one shown above. Among other things, the source is missing. Further, the y-axes of the bottom panels aren’t aligned, wrongly suggesting that taxes (bottom right panel) are often higher than collective expenditures, whereas in fact expenditures are higher than taxes (note that the government also has other sources of income).

Kalshoven and Van Bergeijk’s analysis seems to be strangely unconnected to the broader universe of data visualisation critique (interestingly, one of their sources of inspiration has - somewhat harshly - been described as «a horrible example of economists not recognizing that outsiders can help them»). Some of the most popular topics of chart criticism are missing from Kalshoven and Van Bergeijk’s article: use of colour; if and when it’s ok to truncate y-axes; legends versus labels; and if and how to use the area size of bubbles or icons to represent quantity.

Frank Kalshoven and Peter van Bergeijk, Datavisualisatie in de MEV onvoldoende. ESB 99, nr 4696. Online version here