The current blog will take three different ways of representing the same data set, in order to see how it can be done simply and clearly – or not so clearly. I have taken some samples, and reworked them as a progression throughout this blog.
Although I am discussing the iPad here, this is not a preview about my iPad and Mobile Business intelligence sessions which I’m delivering at SQLBits session in October, or my User Group sessions in Leeds and Surrey this year; however, obviously the iPad is very much in my mind, hence the perpendicular topic of this blog!
The dataset is interesting because it aims to show the impact of the iPad announcement on notebook sales. This study was conducted by NPD, Morgan Stanley Research. CNN Money
has written a short article on the impact of the iPad on netbook sales, which proposes that the iPad is at least ‘partially’ responsible for the decline in netbook sales. The rather dramatic bar chart, which underlines this point, is given here:
There are a few issues with the bar chart:
– The axis doesn’t go from 0 – 100%, which I would expect, given that it is supposed to show percentages. This skews the results slightly; for example, the 70% seems higher.
– 3D gradient issues don’t add anything. Sometimes 3D can make an image look more ‘pretty’. Here, the 3D does not add anything ‘pretty’ or enhance anything about the message of the data
– it’s not clear why the data has been represented as distinct categories when time is continuous rather than discrete
– the big pink arrow shouldn’t have been necessary; the graphic should have been enough.
– there is nothing to make the negative value stand out, or to distinguish it in any way.
There have been other examples of the same data, re-visualised. Here is an example from a wonderful infographic, which has been completed by the Focus Group. I have taken an excerpt of it here since the whole infographic is not the focus of this blog:
The above infographic solves some of the issues of the earlier version, which was reproduced by CNN money.
– There is no 3D
– The big arrows have gone
However, although it is visually appealing, it does repeat some of the earlier issues found in the CNN money chart, since the scale still does not reach 100% on the Y axis. Further, it also introduces some new issues:
– The black background might be visually appealing, but as a ‘best practice’, a white background is better. This allows the representation of the data to dominate the scene, not the background or other non-necessary items.
– hatched lines replace the arrows, to denote the time of the announcement of the iPad and the actual release of the iPad. This is an issue because it is slightly jarring to the eye.
– the month timeline isn’t evenly marked in terms of months; it is therefore difficult to ascertain if the data is skewed horizontally in any way.
In order to improve these representations of the data, I have used Tableau in order to create a simple line graph. This was all that was needed in order to get the message across, without skewing it or obscuring it in any way. Here is my example below, which can also be found on the Tableau Public website:
I have removed the issues found in the earlier visualisations and added some further enhancements:
The negative growth percentage has been highlighted with red colouring
added in clean annotations which do not obscure other parts of the data visualisation
ensured that the Y-axis shows 100% so that the data is not skewed
used a line graph since the X-axis is continuous, not discrete
removed the black background to emphasise the components of the data that provide the message of the data
Although the data visualisation has been improved, there are still contextual answers which the graph cannot answer:
– what about the impact of the iPhone, or other tablets?
– what about the impact of the time of year e.g. post-Christmas sales?
– what about the impact of the impending recession?
Therefore, the initial analysis as described by CNN money simply provided a ‘headline’ message, and further analysis would need to be conducted in order to answer the question more fully. That said, a proper visualisation of the data is a useful tool towards getting the ‘bigger picture’ right, as well as the ‘smaller picture’.
I hope that this was interesting, and look forward to your comments.