A bar chart is a series of horizontal or vertical lines used to make comparisons across various categories. Generally, an X-Y axis is used. Categories may be places along one axis, while it’s values are on the other axis. Negative values can be used as well.
Bar Chart Pros
- Straightforward and easy to understand.
- Can make quick comparisons.
- Quick and easy to set up.
Bar Chart Example
This bar graph show the amount of daylight in Helsinki, Finland for each month in a given year. However, the data here is approximate an will fluctuate slightly from year to year. The bar graph is not ideal for precise data.
Bar Graph Cons
- Excessive data=clutter
- Can be easily manipulated
- Poor design can make it hard to read and subject to misinterpretation.
- Not effective for all data types.
Better Design
An improved design of the graph to the left. Although the the graph on the left is correct, it only covers a small spread. It is making it appear that Amy is ahead by a wide margin, when only five percentage points separate her from Edward. Also other or undecided is not shown. The graph above covers the entire range and accounts for other responses.