5.1.2—Charts and diagrams

A chart should encode the intended quantity with a consistent scale, labelled axes and a legend when needed. Pie charts show parts of a whole; box plots show distribution summaries.

Check that categories do not overlap, totals match the denominator and truncated axes are clearly marked. Use the chart to compare evidence, not to infer causation.

A box plot’s median line and quartiles compare centre and spread without displaying every observation.

A visually larger sector or bar is meaningful only when the scale and category totals are comparable.