I’m not saying it’s right or wrong, I just think that people would know without thinking what it represented.

But two or three segments is probably the way to go.

Then stick to your pie with Trolls and Non-Trolls.

“it is difficult to judge the relative sizes of the bars.” But I don’t want you to judge the relative size of the bars. I want you judge the size of the trolls relative to the total. I don’t think the unstacked bar chart does that as well as the pie chart.

I find that pie charts are useless unless the percentages are shown. Unless the pie “slices approximate easily recognized simple fractions like 3/4, 2/3, 1/2, 1/3, 1/4, 1/6, 1/8, people will not come close to estimating anything correctly.

The stacked bar charts confuse me. While I may be able to approximate the relative size of bars (I prefer nanaimo -http://en.wikipedia.org/wiki/Nanaimo_bar – by the way), the stacking doesn’t provide any immediately meaningful information except the total when the long dimension has large numbers at tick marks. Again, approximating a number near the middle, means approximating those at the extremities and working in.

http://www.add-ins.com/mekko_chart_creator.htm

Lance

The unstacked bar chart is still a better chart. Put a scale on the horizontal axis if you want to show percentages.

In the unstacked bar, the Gremlins are equal to the Orcs. In the stacked meatloaf chart (or whatever you want to call it), it looks like the Orcs are a larger portion. Without a common baseline for the bars, it is difficult to judge the relative sizes of the bars.

Brad -

It’s true that the values in the pie are proportional to the area, or arc length, or angle. The problem is human cognition. When judging linear dimensions (lengths of bars in a chart, for example), we perceive a change in value roughly proportional to the change in length. When judging areas, we perceive a change in value that is only about 70% of the change in area. Angles are similarly misjudged.

I think the pie chart is fine in this case as well. One advantage is that it doesn’t have a start and end (or bottom and top) which can effect the way the data is veiwed in a stacked chart.

While a bubble chart is guilty as charged (bubble diameter is determined by the value, not bubble area), a pie chart is innocent on that account. This is because the radius is the same for one pie slice as it is for the next. Pie slice area, arc angle and circumference are all proportional to the percentage value.