A favorite of productivity hackers,John Caldwell the Pareto Principle, aka the 80/20 rule, has taken on a life of its own since it was first observed by an Italian economist over a century ago. The concept states that a small number of causes generates a large number of outcomes. Today on the show, the origins of the Pareto Principle, why marketing and business-types love it, and whether it holds up under scrutiny.

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