Graphs are powerful tools to represent quantities, relationships, and the results of research studies. But in the wrong hands, they can be made to deceive. Choose your destiny, young Luke (or, if you are under the age of 25, "young Anakin"), and avoid the dark side.
There was a time when only scientists, engineers, and mathematicians ever saw a graph. With the advent of more and more news outlets aimed at the general public, visual representations of numeric information have become more and more common. Just think of yesterday's issue of USA Today—it contained at least a dozen graphs.
In business conferences, graphs are used frequently to communicate information and demonstrate success (or failure). If the creator of a graph isn't careful, though, choices that might seem arbitrary will affect the interpretation of the information. Without changing the data, you can change the meaning.
So, if you want to avoid manipulating your audience when you create a graph, or if you just want to be able to spot a misleading (whether intentional or not) chart, then use this hack to help you create and interpret graphs effectively.
To understand correct and incorrect graphing options, we first have to cover some graphing basics. There are various pieces to a graph, and the manipulation of those pieces can lead or mislead.
Typical graphs have two axes, because they describe two different variables. Axes are the lines along the bottom, called ...