I saw the above graphic about the junior doctors’ dispute in a tweet from the BBC News Graphics twitter account. What struck me was it looked nice but was not very informative. In fact it was confusing at best, and misleading at worst.
It is a good example of how making something look nice does not make it clear. The whole point of a graphic is that it is a visual display of quantitative information that should enable the reader to quickly and easily understand the numbers. On this score it fails. I used the term visual display of quantitative information as that is the title of the data visualisation bible written by Edward Tufte. This is a book that the BBC News Graphics team ought to read.
So what are my beefs with this graphic? I’ll list a few.
- The use of graphic uses area to encode the number of hours at each rate of pay. It is not as quick or instinctive to accurately compare areas, as oppose to lengths. That’s why bar charts are better; the lengths of each bar can be more quickly be compared than areas.
- In the left hand chart, the colour used to show the overtime rates says it is for 120 – 200% of basic pay. This range of values makes it impossible to properly compare the current situation and the proposed rates of pay as it the reader has no idea what the actual % uplift is for each time period. Are doctors currently getting lots of overtime at 200% uplift or is it mainly a 120% uplift? Without knowing this no meaningful comparison to the offer from the government can be made.
- The second graphic with the proposed rates of pay is better than the graphic outlined in point 2 above, in that it does distinguish between overtime uplift rates of 133% and 150%. However, it still is not that helpful as all it is showing is the distribution of the pay rates during the working week and not the impact on total pay.
- The graphics start at 07:00 and then run through for 24 hours to 06:00. This is potentially confusing because if the reader does not follow the times all the way through to the bottom, they may draw the erroneous conclusion that junior doctors only start shifts at 07:00. Why not start the graphic at the start of the day at 00:00? This is what most people would expect.
Graphics are like words, you should think carefully about what you are trying to say, and then choose accordingly. From the above graphic it’s not clear the designer was actually tying to say. The only thing I could quickly take away from it was that the hours that attract overtime were changing, as were the overtime rates. But it was not possible to make any meaningful comparison about the overall impact on pay. Surely that is the most important part of this whole story?
The graphic was nice to look at but not that informative. Sometimes, nice is the enemy of clear.
Finally, just to show I’m not a total grump about the BBC Graphic Team below is a far better graphic from the BBC website story that the tweet linked to. It is simple, unfussy and very easy to read (also given my comments in point 1 above, note how easy it is to quickly compare the lengths of bars).