Stupidest pie chart of the year 2011

I’ve just been looking at the Stupidest bar chart of the year 2011 and I’ve been inspired to submit my Stupidest pie chart of the year 2011. I won’t say from where I obtained it and I’ve drawn the data myself to save from annoying the original authors. And here it is (click to enlarge):

It represents the amount of maternity and paternity leave available in different countries. Pie charts are often not a very good idea, but in this case they are the worst possible idea. Pie charts should be used when the whole pie has some meaning. A whole customer base, individuals living in Nottinghamshire, something like that. The whole of these pies represents- what? The total amount of leave in these countries. This has no real world meaning at all, and the whole point of the pie chart is lost.

Even worse, underneath the pie chart they are forced to write “Spare a thought for parents in the USA and Sierra Leone… paid maternity leave 0 weeks, paid paternity leave 0 weeks.” because you cannot represent 0 on a pie chart! This should have set alarm bells ringing. One better way to plot these data:

This is absolutely factory-fresh out of the box settings, there are many ways to improve this plot and other types of plots which could be used. This plot improves on the previous one by:

1. Better able to compare levels of leave in each country
2. Better able to compare levels of each type of leave
3. No need for data labels which spell out number of weeks in each country and contribute to very low data:ink ratio
4. Able to display zero points which puts the marginal notes about USA and Sierra Leone on the plot!

Code for both:

par(mfrow=c(1, 2))

maternity=c(18, 16, 39, 17, 16, 0, 0)
paternity=c(3, 3, 14, 3, 14, 0, 0)
country=c("China", "Holland", "UK", "Greece", "France", "USA", "Sierra Leone")

pie(maternity, labels=paste(country, maternity, "weeks"), main="Maternity leave")

pie(paternity, labels=paste(country, paternity, "weeks"), main="Paternity leave")

# 2 minute bar chart

par(mar=c(10, 4, 4, 2) + 0.1)

barplot(maternity, names.arg=country, ylab="Maternity leave in weeks", las=3)

barplot(paternity, names.arg=country, ylab="Paternity leave in weeks", las=3)

2 thoughts on “Stupidest pie chart of the year 2011

  1. Chris, you are right that the pie charts are very poor and qualify as a stupidest chart of the year candidate: the pies as a whole and the size of each slice are meaningless; it is difficult to compare a nation’s paid maternity weeks with its paid paternity weeks; and pie charts cannot express zero data points.

    That said, however, your suggested bar charts contain some serious deficiencies of their own:

    (1) The y-axis scales for your two bar charts vary greatly from one another. It is now even more difficult to compare a nation’s paid maternity weeks with its paternity weeks.

    (2) That said, why have two separate bar charts? Instead, display all data in a single bar chart, with maternity and paternity weeks per nation clustered together. (Another option would be a stacked bar chart with one column per nation, paternity weeks at the bottom of the column and maternity weeks at the top, but I’d argue paired columns would more effectively call out significant variances or parity between maternity and paternity weeks).

    (3) Your charts do not take advantage of data sorting to help bring the data alive. I would argue the baseline data point is the number of paid weeks afforded to the mother, so sort the data by paid maternity leave (highest [left side of bar chart] to lowest).

    Now the data can effectively convey the key points the original authors most likely intended:
    * Nations with the most paid maternity leave
    * For each nation, what level of paid paternity leave is mandated
    * Easily see nations with notable variances between maternity and paternity leave and notable levels of parity (e.g., France)
    * Nations with low/zero levels of maternity/paternity leave

    Lastly I suggest Sierra Leone should left off the chart at all, so the x axis consists entirely of “rich nations” whose economy is financially capable of fulfilling a mandate for paid maternity/paternity leave, but doing so – or not doing so – is a choice, based on political will and a nation’s values, which unfortunately are influenced by ideology and/or biases.

    Give these edits a try. See also the charts in this related document:

    • Thanks for this, I will do a follow up post with these edits. I was trying to emphasise “out of the box” performance without things like ordering which it would be unfair to expect ordinary journalists to use, but good points all

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