Must it be exactly 80/20?

No, it is a rule of thumb. What matters is the shape of the cumulative curve: the steeper the start, the better the problem lends itself to targeted action.

How do I choose the measure?

By the goal: counts for quick wins, cost or customer impact for the economically most significant improvement.

Pareto chart

Definition

A Pareto chart is a bar chart of causes or defect categories sorted from most to least frequent, with a cumulative-share curve. It builds on the 80/20 rule: a small number of causes usually produces most of the problems. It shows what to tackle first so the improvement has the largest impact.

Quality control & SPC

Build the chart from counts, costs or time — the ranking of causes may differ by measure, so pick the one that matches your goal (most expensive defects, not most frequent). Repeat the chart after the intervention: the before/after comparison documents the effect.

In quality management and Six Sigma the Pareto chart is one of the seven basic tools alongside the histogram, control chart and Ishikawa cause-and-effect diagram. In DOE the Pareto chart of effects separates significant factors from noise.

In Statistica

Pareto charts are in Statistics → Industrial Statistics & Six Sigma → Quality Control Charts (Pareto chart of defects) and among categorized frequency graphs; DOE produces a Pareto chart of standardized effects with a significance line. Graphs are interactive — categories can be merged and recoloured directly in the chart.

Available from edition: Statistica Desktop

Related terms

Knowledgebase guides

Statistical Advisor: how to pick a method

FAQ

Must it be exactly 80/20?: No, it is a rule of thumb. What matters is the shape of the cumulative curve: the steeper the start, the better the problem lends itself to targeted action.
How do I choose the measure?: By the goal: counts for quick wins, cost or customer impact for the economically most significant improvement.

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Quality control & SPC

Control charts (SPC)Process capability (Cp, Cpk)Design of experiments (DOE)Six Sigma Measurement system analysis (Gauge R&R)All terms →

Updated: September 2026.