The 80/20 Rule: In most problems, 80% of the impact comes from 20% of the causes. A Pareto chart shows you which causes are responsible for the most defects, complaints, or failures — so you can focus where it matters most.
Step 1 — Tally Sheet (Mark each occurrence in real time)
Defect / Problem / Category Tally
| # |
Category / Defect Type |
Tally Marks (make a mark for each) |
Count |
| 1 | | | |
| 2 | | | |
| 3 | | | |
| 4 | | | |
| 5 | | | |
| 6 | | | |
| 7 | | | |
| 8 | | | |
| TOTAL | | |
Step 2 — Ranked Summary Table (Sort highest to lowest count)
| Rank |
Category / Defect Type |
Count |
% of Total |
Cumulative % |
| 1 | | | | |
| 2 | | | | |
| 3 | | | | |
| 4 | | | | |
| 5 | | | | |
| 6 | | | | |
| 7 | | | | |
| 8 | | | | |
Step 3 — Draw Your Pareto Bar Chart
Draw bars left to right, tallest to shortest. Add a cumulative percentage line. Draw a horizontal line at 80% to identify the vital few causes.
[ Draw your Pareto bar chart here — or attach a printed chart ]
Step 4 — Interpretation
| Question |
Your Answer |
| Which 1–3 categories account for ~80% of the problem? |
|
| Which category will we focus on first? |
|
| What is our next investigation step? (5 Whys / Fishbone) |
|
| When will we re-measure to confirm improvement? |
|