A KPI number on its own cannot be judged. It needs a target, a set of bands, or its own recent history.
We put together a guide to the charts that supply that reference: bullet chart, gauge, variance column chart, sparkline, and waterfall. For each one, the question it answers, where it misleads you, and what to reach for when it does not fit.
Great article! This kind of content is always a pleasure to read. I love how it starts from the question each chart answers instead of the chart type itself. Thanks for sharing!