Critical Path
The longest unbroken chain of sequential tasks or activities where delays along that path directly affect the overall completion time of the more general objective.
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Origin
The Critical Path Method was developed in 1956–57 by Morgan R. Walker at DuPont and James E. Kelley Jr. at Remington Rand, working to optimise chemical plant shutdown-and-restart schedules. Run on a UNIVAC computer, the method cut DuPont's costs by approximately 25%. Their findings were formally published in 1959. The U.S. Navy independently developed the related PERT technique for the Polaris missile programme the same year; both became project management standards.
Updated February 22, 2026