Which principle asserts that roughly 80% of outcomes come from 20% of inputs?

Which principle asserts that roughly 80% of outcomes come from 20% of inputs?

• A. Hofstadter's Law
• B. Moving sidewalk
• C. Pareto Principle
• D. 90-90 Rule

Answer: (C)

The Pareto Principle, often called the 80/20 rule, is the idea that a small fraction of causes tends to produce the majority of effects. In real life, a minority of inputs—such as a few key customers, a handful of features, or a small set of tasks—usually generate most of the results. That’s why the statement about roughly 80% of outcomes coming from 20% of inputs fits this principle exactly: the imbalance between where effort is invested and where results come from is common, with the exact percentages varying by situation. This principle helps you focus on the “vital few” inputs that drive most impact. Other options describe different ideas. Hofstadter's Law is about underestimating how long tasks will take, even when you account for that bias; the moving sidewalk idea is a humorous analogy about effort and support rather than how outputs are distributed; the 90-90 Rule refers to timing or effort in projects, not the input-output concentration the Pareto Principle captures.

The Pareto Principle, often called the 80/20 rule, is the idea that a small fraction of causes tends to produce the majority of effects. In real life, a minority of inputs—such as a few key customers, a handful of features, or a small set of tasks—usually generate most of the results. That’s why the statement about roughly 80% of outcomes coming from 20% of inputs fits this principle exactly: the imbalance between where effort is invested and where results come from is common, with the exact percentages varying by situation. This principle helps you focus on the “vital few” inputs that drive most impact.

Other options describe different ideas. Hofstadter's Law is about underestimating how long tasks will take, even when you account for that bias; the moving sidewalk idea is a humorous analogy about effort and support rather than how outputs are distributed; the 90-90 Rule refers to timing or effort in projects, not the input-output concentration the Pareto Principle captures.