Deceptive charts are often misrepresentations of data. Sometimes they are created accidentally because people want to make the chart visually appealing. Sometimes they are create deliberately because people may want to skew data so gaps or trends look more extreme than reality. It is very important that you pay attention and are mindful of these small details! See below for some examples of deceptive charts.
This isn't visually appealing.
Dual axes (or two sets of an individual axis) can make data look like they are correlated but they really aren't. Sometimes this is a deliberate choice or an accidental error. It is good practice to align data appropriately.
In this example, the creator clearly has two separate y-axes (and two different depictions) for the same x-axis. It is a better choice to separate the graphs but align them so the x-axis matches.
Dual axes (or two sets of an individual axis) can make data look like they are correlated but they really aren't. Sometimes this is a deliberate choice or an accidental error. It is good practice to align data appropriately.
In this example, the data share the same y-axis but are between separate intervals. Instead, display the single y-axis and set the lines at their appropriate intervals.