Ordered bar chart of category counts (descending) with cumulative-percentage line on the right y-axis and an 80% reference. Standard 80/20 readout.
Pareto's 80/20 rule: in many distributions, ~80% of the effect comes from ~20% of the causes. The Pareto chart visualises this directly: bars sorted descending by count, with a cumulative-percentage line on the second y-axis and a horizontal reference at 80%.
Standard tool in quality control, root-cause analysis, and product analytics — answers 'which few items are responsible for most of the X?'.
One categorical column.
Dual-axis bar + cumulative-line chart with 80% reference + summary of smallest category set covering ≥ 80%.
The summary 'k categories cover 80%' is the actionable headline — those are the few causes to address first.