📊 Lean Architect · Tyshchenko Lean Academy

Pareto Analysis — the 80/20 Rule

20% of causes → 80% of effects. Find the “vital few”

Vilfredo Pareto and the 80/20 rule
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Vilfredo Federico Pareto · 1906
The Italian economist noticed that 80% of Italy’s wealth belonged to 20% of the population. He checked other countries and found the same distribution. Later, Joseph Juran applied the principle to quality control in manufacturing.
20% of causes
→ 80% of effects / problems
Key idea: Most of the results come from a small number of causes. Find that 20% — and you get 80% of the effect from your actions.
How to build a Pareto chart — 5 steps
1
Collect the data and categories
List every type of problem/cause and its amount (frequency, cost, time)
2
Sort in descending order
The largest value is the first bar, the smallest is the last. Left to right
3
Calculate the cumulative percentage
After each bar: sum of all bars so far ÷ grand total × 100%
4
Draw the bars and the curve
Bars = frequency. Amber curve = cumulative percentage. A horizontal line at 80%
5
Identify the “vital few”
Where the curve crosses the 80% line, every bar to the left of that point is your priority
Where it’s used in Lean
🐟 After Ishikawa
Causes collected → Pareto → 5 Whys on the top 20%
⚙️ OEE and TPM
Breakdown types → Pareto → TPM focus on the top 20%
🏷️ Quality management
Defect types → Pareto → 20% of types = 80% of complaints
💡 Kaizen prioritization
List of ideas → Pareto by impact → top 20% in the first wave
Pareto + Ishikawa + 5 Whys = the full analysis cycle: Pareto — WHAT to solve · Ishikawa — WHICH cause categories · 5 Whys — WHY it happens
Enter your own data — the tool sorts it, calculates the cumulative %, and builds the Pareto chart automatically.
CATEGORIES AND VALUES:
UNIT OF MEASURE: