Ruining the cake with too much icing

January 7, 2013

(This article was originally published at Junk Charts, and syndicated at StatsBlogs.)

Reader Steve S. tried to spoil my new year with this chart he didn't like:


Or maybe he's just chiding me for recommending Bumps charts. This example is very confusing, a tangled mess.

But not so fast.

The dataset has two characteristics that don't sit well with bumps charts. One is too many things being ranked (twenty). Two is too much rank swapping that happens over time (14 periods).

The latter challenge can be tamed by aggregating the time dimension. For some reason, the period under examination was the first half year after the debut of these computers. Do we really need to know the weekly statistics?

We can keep all 14 periods. If so, we should be judicious in selecting the colors, the lines and dashed lines, and gridlines, and so on. In particular, look for a story and use foreground/background techniques to highlight the story.

Here's a version that focuses on the brands that moved the most number of ranks either up or down during this period:


Here's one that tracks how the top five fared over this period of time. It turns out that despite all the noisy movements, not much happened at the top of the rankings:


Not knowing many of these computer brands, I really have no idea why seven colors were used and why different tints of the six colors were chosen. I also don't have a clue why some lines were dashed and others were solid.

Looking closely, I learn that the Sony PC was given a black color because its label does not show up on either side. It was a product that did not rank among the top 20 at the start nor at the end of this time period. This Sony PC should be consigned to the dustbin of history, and yet in the color scheme selected for the original chart, the black solid line is the most visible!


I'd like to see an interactive layer added to this chart that brings out the "information". Two of the tabs can be "top movers" and "top five brands" as discussed above. If you hover over these tabs, the appropriate lines are highlighted.


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