what theory states "that 80% of all work is done by 20% of those doing the work?

Question

& 20% of the work is accomplished by the other 80%?

Answer 1

From Wikipedia:
The Pareto principle (also known as the 80-20 rule, the law of the vital few and the principle of factor sparsity) states that, for many events, 80% of the effects comes from 20% of the causes. Business management thinker Joseph M. Juran suggested the principle and named it after Italian economist Vilfredo Pareto, who observed that 80% of income in Italy went to 20% of the population. It is a common rule of thumb in business; e.g., "80% of your sales comes from 20% of your clients."

The Pareto principle is only tangentially related to Pareto efficiency, which was also introduced by the same economist, Vilfredo Pareto. Pareto developed both concepts in the context of the distribution of income and wealth among the population.

In my case, for example, I wear 20% of the clothes in my closet 80% of the time...

Answer 2

Pareto Principle

http://en.wikipedia.org/wiki/Pareto_principle

Answer 3

probably capitalist theory