Simple Bar Charts — Definition

Definition

A simple bar chart represents one numerical series across categories using bars whose lengths correspond to their values on a common scale. The categories might be wards, products or years, while the measured quantity could be visits, output or expenditure.

Bar width is normally a visual convention; the encoded value is the length along the numerical axis. A simple bar chart should be distinguished from a grouped chart with several series and from a histogram representing class intervals.

Reading the title, units and baseline comes before comparing bars, because identical-looking lengths can mean different quantities under different scales.