A Better Definition of Chart Junk

Maximizing the data-ink ratio sounds like a good idea, but when actually followed to the letter produces terrible and nonsensical results. Here is a more reasonable definition of chart junk that does away with the pretense of a mathematical formula and puts some common sense back into the question of good chart design.

Much has been made of Tufte’s famous data-ink ratio, and many people like to rail, privately and online, against chart junk. In short, the data-ink-ratio defines the amount of information your chart elements (“ink”) are providing, with the goal of maximizing that ratio. Since we can assume that the information is constant, this means we need to minimize the amount of ink. Any ink on your chart that does not convey data is considered junk.

While this extremely reduced definition makes for great flame war fuel, it places the emphasis on the wrong question, and when property followed, leads to largely nonsensical charts (this example is from Stephen Few’s recreation of Tufte’s argument).

The first issue is the whole notion of ink. What does that even mean? If you live in a world of black ink on white paper, that may be a reasonable criterion. But add color and the whole thing breaks down. Color can be used well and can be terrible. Reducing ink does not tell us anything about that. The same is true for interactions like mouse-overs, sorting, and other conveniences our modern visualization machines afford us.

There is a parallel here [...]