# Deviation Bar Graph – Definition & Examples

-

Deviation bar charts are important for graphic presentation of net quantities such as surplus or deficit, net profit or loss, net of imports, and exports which have both positive and negative values. The positive deviations (e.g., profits, surplus) are presented by bars above the base line while negative deviations (loss, deficit) are represented by bars below the baseline.

Deviation bars are also sometimes known as Bilateral Bar Diagrams and are used to depict plus (surplus) and minus (deficit) directions from the point of reference.

The deviation bars allow us to make quick comparisons between two different sets of responses for the same category of data. They are helpful in giving us a quick visual overview of how there are two different responses to the same set of values of the independent variable.

### Example of a Deviation Bar Graph:

Consider the following set of data about the trade surplus and deficits of a country.

The deviation bar chart below shows the degree of surplus or deficit in the trade export/imports of a country. If the total exports exceed the total imports then we have a trade surplus and this is represented by the blue bars which rise upwards. On the other hand, if the total exports are less than the total imports we have a trade deficit and this is represented by red bars which point downward.

For example, in the above diagram for the year 1994, there is a trade surplus of 15 million dollars meaning that the total value of the exports exceeds the total value of the imports by 15 million dollars. On the other hand in the year 1996, the imports exceed the exports by a total value of 8 million dollars.

#### Remarks:

1. One of the disadvantages of a deviation bar chart is that it cannot be used if there are three kinds of reponses available to a particular variable. For example if we were to ask a group of 100 people if they like coffee ot not and the answers allowed are YES or NO then the data can be represented by a deviation chart. But if three different reponses such as YES, NO and NEUTRAL are allowed then the data cannot be plotted using deviation bar graph.
2. Another demerit of deviation chart is that it gives us the differences in the responses but does not show the absolute value for each of the two kinds of responses.
3. The main advantage of the deviation chart is that it useful for making quick visual comparisons.

Hey 👋

I have always been passionate about statistics and mathematics education.

I created this website to explain mathematical and statistical concepts in the simplest possible manner.

If you've found value from reading my content, feel free to support me in even the smallest way you can.