Which problems should I fix first?
Build a Pareto chart from category counts, with the cumulative line and the vital-few cut.
Pareto Chart · analyze · White Belt · free, no account needed
Use this when
- You have counts by category and need to know where to start
- A team meeting produced ten ideas and you need evidence, not opinion
- You suspect a few causes carry most of the problem
Pareto Chart
sandboxShow the data behind this chart
| Rank | Category | count | Share | Cumulative |
|---|---|---|---|---|
| 1 | Password reset did not persist | 142 | 43.6% | 43.6% |
| 2 | Issue recurred within 48h | 87 | 26.7% | 70.2% |
| 3 | Wrong team assigned | 41 | 12.6% | 82.8% |
| 4 | Resolved without contacting user | 23 | 7.1% | 89.9% |
| 5 | User could not follow instructions | 14 | 4.3% | 94.2% |
| 6 | Hardware fault misdiagnosed | 9 | 2.8% | 96.9% |
| 7 | Duplicate of another ticket | 6 | 1.8% | 98.8% |
| 8 | Other | 4 | 1.2% | 100.0% |
Ranked by frequency. If these categories differ sharply in cost or severity, the ranking may point at the wrong one — try weighting by impact and compare.
3 of 8 categories reach 80% of the total. The 80% line is a convention, not a rule your data has to obey — where you actually cut is a judgement about effort and capacity.
One per line: a name, then the value. Paste straight from a spreadsheet — tabs, commas, £ signs and thousands separators are all understood.
How this is calculated
Categories are sorted by value, descending. The cumulative percentage is the running total divided by the grand total, times 100. Ties are broken alphabetically so the chart does not reorder between runs.
Source: Montgomery, Introduction to Statistical Quality Control 7e, §5.4. The “vital few and trivial many” is Juran’s formulation, and Juran later noted he had misnamed the principle after Pareto.
How this is calculated
Categories sorted by descending frequency; cumulative percentage = running total / grand total x 100. The 80/20 line is drawn as a reference, never as a rule the data must obey.
Source: Montgomery, D.C., Introduction to Statistical Quality Control 7e, Sec. 5.4 (Pareto chart).
Learn the method
- Pareto: finding the few categories that carry the problemWhite Belt · 12 min · free