Deep Work: Rules for Focused Success in a Distracted World

by Cal Newport

The Law of the Vital Few*: In many settings, 80 percent of a given effect is due to just 20 percent of the possible causes. For example, it might be the case that 80 percent of a business’s profits come from just 20 percent of its clients, 80 percent of a nation’s wealth is held by its richest 20 percent of citizens, or 80 percent of computer software crashes come from just 20 percent of the identified bugs. There’s a formal mathematical underpinning to this phenomenon (an 80/20 split is roughly what you would expect when describing a power law distribution over impact—a type of distribution that shows up often when measuring quantities in the real world), but it’s probably most useful when applied heuristically as a reminder that, in many cases, contributions to an outcome are not evenly distributed.