The Italian sociologist Vilfredo Pareto (1848–1923) recorded a “maldistribution” between causes and effects in economic statistics. It’s an observable fact that a minority of reasons—nominally around 20%—tends to produce a majority—80%—of the results.
Most Effects Come from Relatively Few Causes
More than a century later, the Romanian-American quality control pioneer Joseph Juran (1904–2008) embraced Pareto’s notion and demonstrated that 80% of all manufacturing quality defects are caused by 20% of reasons. Juran urged managers to identify and address the “vital few” or the “critical few “—the small fraction of elements that account for this disproportionally large fraction of the effect.
This Pareto Law, 80/20 Rule of Thumb, Zipf’s Principle of Least Effort, Juran’s Law of the Vital Few, 80-20 Thinking—call it what you want—permeates every aspect of business and life. Now that you know about it, you’ll start seeing it everywhere.
A fifth of your customers accounts for four-fifths of your sales. 20% of your employees are responsible for the majority of your firm’s productivity. 20% of your stocks will be responsible for 80% of your future gains. You tend to favor 20% of your clothes and wear them 80% of the time. You spend 80% of your socializing time with 20% of your friends. 20% of the decisions you’ve made during your life have shaped 80% of your current life. 80 percent of the wealth tends to be concentrated with 20 percent of the families.
The Pareto principle is a state of nature (the way things happen) and a process (a way of thinking about problems.) The 20% are the sources of the most significant potential impact.
The Remarkable Variance of Contributors and Effects
.jpg "'The 80-20 Principle' by Richard Koch (ISBN 0385491743)")
Richard Koch’s 80/20 Principle: The Secret to Achieving More with Less (1999) elaborates on using this seminal prioritization principle. “The 80/20 Principle asserts that a minority of causes, inputs, or effort usually leads to a majority of the results, outputs, or rewards. … The winners in any field have … found ways to make 20% of effort yield 80% of results.”
Koch explains ad nauseam that most of us work much too hard and produce much less in relation to what could be produced. If trying harder hasn’t worked, perhaps it’s time to try less.
- Invest your time and effort more wisely. Don’t address the less significant elements. “Most things always appear more important than the few things that are actually more important.” Examine what you do of low value. In other words, eliminate or reduce the 80% of efforts that produce less-significant results.
- Know when to stop. Once you’ve solved the 20% of the issue to deliver 80% of the impact, any further effort can only achieve diminishing returns.
Idea for Impact: In most areas of human activity, just 20% of things will be worthwhile.
Recommendation: Speed-read Richard Koch’s 80/20 Principle. It’s an excellent reminder that not all effort is equal, so it pays to focus on what matters most.
Embrace the “80-20” frame of mind in everything you do—at work and home. Unless you want to spend every waking hour working, it’s essential to learn how to focus your efforts on the most promising, impactful aspects of what needs to be done.
- Realize that few things really matter in life, but they count a tremendous amount. These vital things may be challenging to discover and realize, but once you find these things that really matter, they give you immense power—the power that gives you more from less. Spend a disproportionate amount of time and energy making sure these decisions are made well, and you put yourself in the best position you can in the process.
- If you want to improve your effectiveness at anything, focus only on what matters most. Be extraordinarily selective—spend time resourcefully on the few essentials that matter the most and little or no time on the massive trivia that engulfs most of your time.
Say you’re in the market for a laptop but just can’t bring yourself to pick out the right model. You’ve spent countless hours comparing different models, visiting various websites, reading reviews, exploring stores, and researching all the available features, even though you’re unlikely to use most of them. 
A long time ago, I heard the managerial maxim, “you will move as fast as you can make decisions.” Amen to that..jpg "'Thinking, Fast and Slow' by Daniel Kahneman (ISBN 0374533555)")
Thinking, Fast and Slow is an eye-opener in various ways. It can be a frightening .jpg "'You Are Not So Smart' by David McRaney (ISBN 1592407366)")
Making decisions is all about 
Beware exaggeration of a kernel of truth. For instance: indeed, many of us don’t realize our full intellectual potential; but that doesn’t give credence to the notion that most people use only 10% of their brainpower. Besides, beware of overstatements of small differences. Sure, men and women tend to differ somewhat in their communication styles, but declaring that “men are from Mars” and “women are from Venus” is taking a kernel of reality to an extreme, not to mention coercing psychology into stereotypes.
In 1982, Tylenol commanded 35 percent of the over-the-counter analgesic market in America. This over-the-counter painkiller was the drugmaker’s best-selling product, and it represented nearly 17 percent of J&J’s profits. When seven people died from consuming the tainted drug, Time magazine wrote of the tragedy’s victims,
When the second outbreak of poisoning occurred four years after the first, Burke went on national television to declare that J&J would only offer Tylenol in caplets, which could not be pulled apart and resealed without consumers knowing about it.
It’s terrible optics for an elected official to leave his constituency while it’s in the midst of a crisis.