An Italian engineer found a lopsided pattern in wealth. Fifty years later, an American factory expert gave it his name — and later admitted he had stretched it.
← Maslow's Hierarchy of Needs · All the tools · The Fishbone Diagram →
Easier version: read this lesson at A2/B1 level →
Ten items. Say your answer out loud before you reveal it.
Read the sentence, guess the meaning of the word in bold, then reveal.
The three words are: rule of thumb · wealth · inequality. Read each meaning, say the word, then reveal.
One missing word fits every phrase in the group. Say it, then reveal.
Read each part. After it, answer the quick check from memory, then discuss one question.
Vilfredo Pareto was born in Paris in 1848, to an Italian father and a French mother. He trained as an engineer in Turin and spent years managing railways and ironworks in Italy. He was clever, argumentative and very interested in politics — so interested that, in his forties, he changed careers completely and became an economist.
In 1893 he became a professor at the University of Lausanne, in Switzerland. There, he did something unusual for the time: instead of just arguing about how wealth should be shared, he collected numbers about how it was shared. He studied tax and income records from different countries and different centuries.
What he found surprised him. Again and again, the distribution had the same lopsided shape. A small proportion of the people had a very large share of the wealth, and the vast majority had very little. In 1896 and 1897, he published his results in a book called Cours d'économie politique.
1. What was Pareto's first career?
2. What was unusual about his method?
3. What pattern did he find?
1. He was an engineer (railways and ironworks).
2. He collected real numbers — tax and income records — instead of only arguing about how wealth should be shared.
3. In many countries and centuries, a small proportion of people held a very large share of the wealth.
The famous version of the story says that Pareto found that 20% of the people in Italy owned 80% of the land. Many books add a charming detail: that he first noticed the pattern in his garden, when he saw that 20% of his pea plants produced 80% of the peas. There is no good evidence for the garden story. It is probably a legend added later, because it makes the idea easy to remember.
Pareto himself was interested in wealth, not in a general rule for everything. He died in 1923, long before his name became attached to the phrase “the 80/20 rule”.
That happened because of a quality expert named Joseph Juran. Born in 1904 in what is now Romania, Juran moved to the United States as a boy and grew up poor in Minnesota. He became an engineer at Western Electric, a huge telephone factory near Chicago, where he inspected products for defects.
1. What is the famous version of Pareto's finding?
2. Is the pea garden story true?
3. Where did Juran work as a young engineer?
1. That 20% of the people in Italy owned 80% of the land.
2. Probably not — there's no good evidence; it's likely a later legend.
3. At Western Electric, a big telephone factory near Chicago.
Juran noticed that factory problems were lopsided too. A handful of causes produced the vast majority of the defects. If a factory fixed those few causes first, it could solve most of its problems quickly. In the 1940s, looking for a name for this idea, he remembered Pareto's charts of wealth and called it the Pareto principle. He described it as “the vital few and the trivial many”.
Years later, Juran admitted that he had stretched things. Pareto had never stated a universal rule; Juran had given him credit for a much bigger idea than he had actually proposed. Juran also changed his own phrase to “the vital few and the useful many”, because the “many” small causes still matter.
Today, the 80/20 rule is everywhere. Shops find that a small share of their products bring in most of their money. Software companies have found that fixing a small share of the bugs removes most of the crashes. Coaches, doctors and teachers use it too. But the numbers are a rule of thumb, not a law of nature: the real split might be 70/30 or 95/5, and the two numbers don't have to add up to 100.
1. What did Juran notice about factory defects?
2. Why did Juran change “trivial many” to “useful many”?
3. Is the split always exactly 80/20?
1. A handful of causes produced most of the defects.
2. Because the many small causes still matter; they aren't worthless.
3. No — it's a rule of thumb; the real split can be 70/30, 95/5 and so on.
A Pareto chart sorts causes from biggest to smallest. The bars show each cause; the red line adds them up as you go. Where the line crosses 80%, you have found your vital few. Here, 100 complaints at a small café:
A small online clothes shop had 200 returns last month. Which causes are the vital few (together about 80%), and which are the useful many? Add them up, then choose.
1. Vital few — the biggest cause, 55% on its own.
2. Useful many — only 6%.
3. Useful many — 8% — the third-biggest cause, but outside the top two.
4. Vital few — 25%; with “wrong size” it makes 160 returns = 80%.
5. Useful many — 5%.
6. Useful many — only 1% — although, if the quality problem is serious, it may still deserve attention.
It's not a law. The split changes from case to case; don't force your data into 80/20.
Small causes can be serious. One rare safety problem may matter more than a hundred common annoyances.
It can be used unkindly. “Twenty per cent of customers bring eighty per cent of the profit” can lead a company to ignore everyone else.
The 80/20 rule is all about how much and how many. At B2, you need a wide range of phrases to describe proportions — not only percentages.
Write one word in each gap.
1. Only a of people — four or five — knew the secret.
2. The vast of the town's workers had jobs at the factory.
3. Our flat is small: the new one has as many rooms — six instead of three.
4. There was hardly food left after the party.
5. people enjoy paying tax, so the government's new idea was not popular.
1. handful
2. majority
3. twice
4. any
5. Few
Look at the café chart in The Tool tab. Complete each sentence.
1. Slow service caused of all the complaints. (a fraction)
2. Cold food caused as many complaints as noise. (a multiple — roughly)
3. of the complaints were about Wi-Fi. (a small part — a phrase)
4. Together, two causes were responsible for the of complaints. (a large part)
1. half
2. four times (30 compared with 7)
3. Only a few / A small minority / Hardly any
4. (vast) majority
Now describe your own week in proportions: what takes up the majority of your time, and what gets hardly any?
Look for the vital few in your own life. Choose a task, start the timer, and talk.
Which few activities give you most of your results — at work, in study, or in your health? Which give you almost nothing?
Think of something that often goes wrong for you. Are most of the problems caused by a few causes? Which ones?
Choose a place where a few people have most of something, such as money, attention or power. Is that a problem? Why?