In this lesson, you’ll learn the definition of misleading graphs and explore some examples to see how and why they are produced. Following the lesson, you’ll have a chance to test your own understanding of misleading graphs.
What Are Misleading Graphs?
A graph is a diagram showing the relationship between or among variables. Usually a graph shows the relationship between two variables: the independent variable and the dependent variable. And usually a graph is depicted on an x-axis and a y-axis, but this is not always the case. For example, the pie chart is considered a graph that does not have an x-axis and a y-axis.Graphs are great tools for visually representing complex data.
But they can also be misleading if the source uses them incorrectly.Misleading graphs are graphs that distort data to make it look better or worse than it actually is, which can lead to incorrect conclusions. Sometimes, unintentional errors can lead to misleading graphs. But, unfortunately, misleading graphs are usually created to intentionally skew data. There are three different ways that graphs can be misleading: axis and scaling manipulation, missing information, and sizing.
Axis and Scaling Manipulation
Axis and scaling manipulation is a sneaky way of producing misleading graphs. Here, when people compare two graphs, they may not notice that the scales are different. They may just see the bars or line on the graph and make a quick determination about the data. Let’s take a look at a hypothetical example.
Magic Dust is a company that has created an extraordinary substance that can make people fly. They’re a multi-billion dollar company that has been in business for 20 years. By comparison, Flying Powder is a relatively new company that has only been in business for five years. For advertising purposes, they’ve conducted a survey to see how many people prefer Flying Powder to Magic Dust and used the following graphs to promote their results:
In these graphs, Flying Powder looks like it’s becoming more popular. But the graphs are misleading. Look at the percentage scales on the left-hand side! Flying Powder’s scale does not incorporate anything above 20%.
As a result, the slope of the line is greatly exaggerated. In reality, 85% of people still prefer Magic Dust, while only 15% prefer Flying Powder.
Sometimes, a company or a financial institution will want to show that their returns have risen steadily over the past several years. Therefore, any drops in returns that look bad might be excluded from a graph. Look at the two graphs below.
The first graph includes all of the data, while the second graph excludes some of the data points.
Imagine a pictogram graph where the pictures are very different in size even if their value is the same, or a pie chart where pieces of the pie do not represent the percentage that makes up that piece. For example, consider the pie chart below, which supposedly shows the approval rating of four competing politicians.
The politician with the 5% approval rating posted this pie chart. Here, it appears that he’s neck-in-neck with the politician with the 11% approval rating because the sizes of their pie slices look very similar.
Although some close reading can help you can identify misleading graphs, they can be deceptive if given a brief glance or flashed quickly on a news station or advertisement.
Whether for business or political reasons, misleading graphs are a common tool used give the impression that data is better or worse than it is in reality. Remember that graphs are diagrams showing the relationship between or among variables.
Although misleading graphs may be developed in error and unintentionally, they can also be developed intentionally to misrepresent data points. Graphs can be misleading if they manipulate the scales or axes, omit information, or alter the sizing to make the graph look more desirable for a company’s or an individual’s purpose. In general, graphs use an x-axis and a y-axis; other graphs may use pie charts.