80/20 rule: Nature's Law or An Observation????

I do not remember exactly how i learned about 80/20 rule. May be, i read it somewhere or heard it from the mouth of somebody, but it interested me a lot while i was in engineering. Today i happened to recall this rule again as i want to share something interesting. I googled to understand this rule again.

80/20 rule is true in many instances. It is very simple to understand. According to this rule, 80% of the wealth in this world is contributed by about 20% people.It is also called Pareto Principle. It can be applied to any field; science, social or management.

Other example:

1) 20% parts in a car/vehicle make up 80% of total cost
2) 20% people produce 80% results in organization/party/country
3) 80% of monalisa picture was painted in 20% time etc

PS: 20% and 80% are not exact figures but approximations;

This rule may seem juss an observation to us. This can not be denied. But it may give more meaning to an economist. Neither it is nature's law nor can be be proved all the times mathematically. It only helps us get a picture of whats happening around us in a simple and interesting way.

Read about this:
1)link: http://en.wikipedia.org/wiki/Pareto_principle
2) http://betterexplained.com/articles/understanding-the-pareto-principle-the-8020-rule/