Why the Legend is Doing You More Harm than Good

If you listen to renowned chartmaker and Yale professor Edward Tufte – and believe me, I usually don’t – then you would say that a good Gantt chart should not need a legend. Tufte says any chart’s colors and formatting should be so self-explanatory that a legend is not necessary. In fact, he would go on to say, it is clutter, or “chartjunk” as he calls it, that should be stripped off the screen entirely.

In this case, I think Tufte has a point, and I must disagree with my colleague Jay. In most cases, if we judge Gantt charts by how well they communicate project status, a legend is probably doing you – and your audience – more harm than good. Continue reading

1 : 0.618 – the Gold Standard in Aspect Ratios

We’ve gotten a handful of questions on the Support line about how to change the aspect ratio (width:height ratio) of a project view, to make your Gantt chart appear wider, narrower, taller, or shorter for your audience. Here’s how: In the Project-View Properties menu, click on the Page Layout tab (shown below). At the top, you can manually change “Document width” and “Document height” settings, which for U.S. customers are measured by default in inches.

Document width and height controls in Project-View Properties

But what, you may ask, should you change the aspect ratio to? It turns out that by asking that question, you have stepped into a debate about the ideal width to height ratio that has been raging since antiquity.

Many scholars believe the ancient Greeks favored a width to height ratio known as the Golden Section. The Danish engineer Vilhelm Marstrand wrote in 1922, “Division of a line according to the Golden Section … implies that a given line is divided in two pieces, a and b, such that the shorter piece … is to the larger … as the longer is to the whole line.” In other words,

(a/b) = (b + (a/b))

Setting b (the width) to 1 and solving for a, we get

a = (sqrt(5) – 1) / 2

… or 0.618.

Fine, but who cares? Well, scholars have deduced that a number of ancient edifices roughly adhered to the Golden Section, including the Parthenon in Athens:

The Parthenon in Athens

But that doesn’t tell us why the ancient Greeks liked an aspect ratio of 1 : 0.618 – and the Greeks didn’t really tell us either. All in all, the best anyone can come up with is that it just looks pretty.

So what do OnePager project views look like when they adhere to the Golden Section? Here is a project view with a Document width of 14 inches. If we multiply that width parameter by 0.618, we get a suggested Golden Height of 8.65 inches (since OnePager won’t allow the second decimal place, we’ll have to round to 8.7 inches). The project view looks like this:

Gantt chart with Golden aspect ratio

Pretty nice, huh? It also fits perfectly in a PowerPoint slide (those Microsoft propeller-heads must know their stuff!).

Now let’s look at the same project view if we make the aspect ratio 2 : 1 (meaning the project view is twice as wide as it is tall):

Gantt chart with 2:1 width:height ratio

This is not so nice – the project view is obviously stretched out, and if you paste it into PowerPoint there ends up being a lot of white space on the top and bottom of the slide.

If we make the aspect ratio 1 : 2 (meaning a 14-inch-wide project view has a height of 28 inches), it looks even worse:

Gantt chart with 1:2 width:height ratio


In conclusion, for reasons we don’t quite understand, it’s clear that if you’re in search of an aspect ratio, you could do a lot worse than the Golden Section. Just multiply your Document width by 0.618 and enter the result as Document height on the Page Layout tab of Project-View Properties. Then go out to lunch – may I suggest a Greek salad?