The Psychology of Quality and More

Pareto Chart

Where there are many items with small values, they may be lumped together into an 'other' category and put on the right.

Typically, the chart is used to highlight problems or things requiring work. The ideal chart is 'spiky', with a high left bar, as this clearly shows the best thing on which to work. 

Note that the height of the bars implies priority. Usually the bars are a count of defects or problems. They may be weighted, for example by cost, to improve the prioritization effect. 

See also:

Toolbook chapter: Pareto Chart