The 20%

To find which few to attend to, find which few causes are producing most of the results — in many complex systems, under a fifth produces over four fifths.

A Few says to attend to a few of the highest quality. This chapter says how the few are found, and the method is to look at causes rather than at importance. Most of what happens in a complex system is produced by a small part of it. Locate that part and you have located where effort actually converts into outcome; miss it and you can work very hard on the other eighty percent for years.

The proportion is a rule of thumb with a long history in quality and reliability work, and it is offered here as one — in many complex systems, not in all, and less than twenty producing more than eighty rather than any exact split. It is an estimate about shape, not a measurement of any particular system, and the useful part is the asymmetry, which holds far more widely than the numbers (Theory Of Constraints, Bottleneck, Limiting Factor).

The chapter adds two things that make it more than a familiar maxim. The first is that it nests: the twenty percent of the twenty percent are a few. Apply the lens once and you have a fifth; apply it again and you have the handful that a person or a body can actually hold (A Few, One moves a few, a few moves 3%, 3% moves 20%, 20% moves 80%).

The second is a chain of diagnosis that runs deeper than the results themselves: results are best read as conditions, which arise from systems, which are transformed by transforming the few that transform the twenty. That sequence is the whole difference between attacking symptoms and attacking causes. A result is an event and cannot be argued with; a condition is what keeps producing events of that kind; a system is what holds the condition in place; and the few are the points where the system will actually move (Root Causes, Meta System, The three nested holarchies — Issues, Opportunities, Goals, Design To The Goal).

Used honestly it is a subtraction tool as much as a selection one. Finding the fifth that carries the load is also finding the four fifths that do not, and stopping those is usually the faster half of the improvement (Waste, Prune, Continuous Improvement).

Also called: the vital few · the 20% of the 20% Stands on: A Few · Root Causes · Theory Of Constraints · Value Opens onto: One moves a few, a few moves 3%, 3% moves 20%, 20% moves 80% · Bottleneck · Limiting Factor · Waste · Meta System · Our Core Ways · Continuous Improvement · Attend To The Most Important Things First · Design To The Goal · Maximum reuse In play: the table — in any look-back that asks not what went wrong but what few things decided this Sources: LIØNSBERG Wiki Books/The Wisdom of the Way/3. The 20%.md (unmarked, six lines) · the same book's chapter 2 · lionsberg.wiki: The Wisdom of the Way Open: The chapter gives the proportion without a source; it is an inherited rule of thumb, not a finding of this corpus. · The results-conditions-systems-few chain is stated once and used nowhere else in the book.