Bar Chart: How to understand it

The Quality Toolbook > Bar Chart > How to understand it

When to use it | How to understand it | Example | How to do it | Practical variations

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How to understand it

Numeric measurements may be organized in tables to make them easier to understand, but this format still lacks visual impact, with trends and relative sizes difficult to discern.

The Bar Chart shows measurements in discrete physical bars, as in Fig. 1. The area of the bar is proportional to the size of the measurement, and gives a better visual impression of its size than a point or vertical line. Where there is more than one bar, then the relative sizes can be seen, even between physically separated bars. Even complex trends across multiple bars may be apparent (although Line Graphs and Control Charts can be better for measuring trends).

Fig. 1. Numbers into bars

The Bar Chart is a flexible format which can be used in a wide number of situations (this may be contrasted with the specific purpose of the Histogram or Pareto Chart). The independent nature of each bar enables even quite disconnected items to be compared.

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