Vilfredo Pareto, an Italian economist from the turn of the 20th century, noticed that 80% of the land in Italy was owned by 20% of the citizens. He further noticed that in general, income, wealth, land ownership, and other such economic things followed a similar distribution. He formalized this observation into "Pareto's Law", which states that distribution of wealth follows a logarithmic relationship:
Log N = log A + m ( log x )
Where N is the number of income earners who earn higher than x. A and m are constants, determined by the specific system under study. The 80-20 rule, also known as the "Pareto Principle", is a specific instance of this relationship.
Dr. Joseph Juran, management expert and quality pioneer, was the first to apply the 80-20 rule outside of economics, specifically applying it productivity, giving us the most popular statement of the 80-20 rule: 80% of the work is done by 20% of the workers.
Until recently, the 80-20 rule, or logarithmic distributions in general, were rarely studied outside the fields of economics or management theory. However, recent advances in network theory have found that Pareto's Law it is equally valid for a number of other systems, both naturally occurring and man-made systems, including molecular biology, the spread of viruses (both organic and cyber varieties), the organization of terrorist cells, the infrastructure of the Internet, the organization of the World Wide Web, and the "Six Degrees of Kevin Bacon" phenomenon - a real phenomenon, although it is not unique to Kevin Bacon.
In any case, the next time you feel like you're doing 80% of the work, at least you can take comfort in knowing it's not just your imagination.
WHO GOT IT RIGHT: Pete Daggett, JP Weigt, Duke Duquette, Kathi Reynolds, Marika Thiessen, Dennis Rodgers, Kay van Nielen, Kari Hermunen, Dave Cooper, Marc Quinlivan, Bob Milligan, Robert Berkowitz, Dustin F, David Fye, Luz Velasco, Mark Mageau, Igby, and Samantha Green.