This week was a makeover of a Financial Times article on the UK economy since the Brexit referendum using data from the OECD.
The original visualisation allows us to easily see the UK, but doesn’t allow us to compare to another G7 country as there is no labelling of the other lines or ability to highlight. The chart also lacks context around when the Brexit vote occurred and what the historical patterns have been; does the UK usually have slower growth than the rest of the G7? Missing 2017 Q2 data is a bit of a shame.
I’ve gone with three key elements in my makeover:
- Retain the line chart and highlighting of the UK, but show a wider period of time and highlight the referendum date
- Show the range of growth across the G7 without showing too many lines. Instead allow the user to choose which G7 country to compare to
- Provide a ranking table to highlight the low ranking for the UK in the last two quarters
The viz is also available on Tableau Public.
My usual approach would be to plot all of the G7 countries as individual lines in a deemphasised colour. This week I wanted to experiment with showing the range of data in a different way. I had hoped that a light area chart would allow me to highlight the UK in red, show another selected country in a mid-grey and still see the G7 range in the background. Whilst the approach does allow the user to get a better idea of stability / variability for each country as they explore the data, the area chart doesn’t really sit in the background when it comes to interacting – e.g. hover over.
The area chart has two parts with the bottom part being shown in white to give the impression that you’re just seeing one area. This required calculations based on min/max values to get the two parts. An additional challenge was that Tableau doesn’t handle area charts crossing the 0 line particularly well (or didn’t for me at any rate – I ended up with empty shards in the chart!). To work around this I calculated an offset and pushed all data points up by that amount so that everything was above 0. The real, none offset, values are used for labels and tooltips and a reference line was added for a fake 0 line. Upshot: it was a lot of work and fudging and perhaps not worth it. Feel free to download the workbook from the Tableau Public page linked above to see what you think.
I like the way the table at the end tells the ranking part of the story in quite an effective way. I prefer it over a bump chart in this case and in hindsight perhaps the table was actually all that the makeover needed!