Statistics are an effective tool that can quickly share facts and ideas. One disadvantage, however, is that they are easily manipulated, and can deceive your audience. Sometimes this is done on purpose, because if you can make numbers work in your favor, people are more likely to buy from/do business with you. Sometimes this is done on accident, simply by creating a poor visual product.
To illustrate my point, here are a few poorly constructed graphs:
A pie chart was a poor choice to display this information because A) the numbers provided don't add up to 100%, and B) 4/5ths of the data is barely represented.
3-D Graphs are never a good idea. They skew your perspective, making it difficult to plot any specific point on it. There are also no labels on either axis, so it's impossible to tell what this graph is supposed to represent.
Because these graphs are so unreadable, it automatically makes your information unreliable. Unless it is absolutely essential to the viewer, they won’t spend more than about 5 seconds trying to decipher your graph. That doesn’t mean you have to make it boring and super straightforward though. Graphs can be both easily-read and visually interesting, like this:
The graphs are straightforward, but the colors make it interesting to look at. The viewer doesn't have to search for a key, which increases readability exponentially (granted, the information is unreadable because of its size, but visually the graphs are better).
The differences between the graphs are obvious. Listed below are a few suggestions to help make effective, honest, readable graphs.
Choose the Right Graph
Different information needs to be displayed in different ways. A pie chart should only be used when the numbers provided equal 100% (a whole). A bar graph is generally used to show information over time, or to show comparisons, so you wouldn’t really want to show portions of a whole in the form of a bar graph. There are many different kinds of graphs, this document provides a little more information about them. Just remember that your content should be presented in a way that makes sense.
Always Provide a Key
Without a key, your graph is useless. No one will know what your graph is about, or how to read it. The viewer shouldn’t have to hunt for your key, either. It should be very easy to find, and easy to read. Some information isn’t meant for the masses; it is meant for specialists. You don’t have to dumb down your content (nor should you), but when a graph is simple, it is easier to share information with all parties involved.
Don’t Use 3-D
You may think it’s cool, but it’s not. It’s confusing, and because of the skewed perspective, it becomes nearly impossible to read. Just don’t do it.
Be Careful With Your Colors
It can be tempting to use bright, exciting colors to make your graph bright and exciting, but more often than not a bunch of bright colors all right next to each other only cause headaches and strain on the eyes. If you want to use a variety of colors, make sure they are calmer tones. It seems boring, but it can be nice to use a monochromatic scheme (all different values of one color). Just be sure that the value of each color is different enough that it is easy to tell the difference. When they are too similar, that can also make your graph difficult to read.