One of the main qualities of a Bar Graph is the ability to order bars by using the same attribute.
Horizontal Bar Graphs are often used when the labels for the categories are very long and there are many categories e.g. 20-50. It is easier to view them by scrolling down.
Tips
· When plotting a Bar Graph, do not plot the bars randomly like in Example 1
· Also do not add grid lines to make the user guess the relative sizes of the bars like in Example 1
· Instead add the data labels to the bars like in Example 2
· Order the bars in ranking order A-Z or Z-A shown in Example 2 and Example 3
Exceptions
The exception to the rule of ordering a Bar Graph is when:
· a specific order is required e.g. alphabetical
· the time period category is displayed. In this case, the order is from most recent to the least recent as seen in Example 4.