Glossary · approach
Critical Path Method
Foundational deterministic project-network technique: given activities with fixed durations and precedence, compute earliest and latest start/finish times and identify the longest path that drives project duration.
CPMCritical Path Method (CPM)Kelley-Walker Method
The Critical Path Method (CPM) is the foundational project-network operations research technique of Kelley and Walker (1959). Given a set of activities with deterministic durations and precedence constraints (modelled as an activity-on-arrow or activity-on-node directed acyclic graph) it computes, by a forward pass and a backward pass, the earliest start, earliest finish, latest start and latest finish of each activity. The critical path is the chain of activities whose total slack is zero; its length equals the minimum project duration. Non-critical activities carry total slack (delay tolerated without slipping the project) and free slack (delay tolerated without slipping the next activity). The algorithm runs in polynomial time on the activity graph and underpins every modern project-management tool. CPM assumes deterministic durations and unconstrained resources; the probabilistic extension is PERT, the resource-constrained extension is RCPSP, and Goldratt (1997) added a buffer-based critical-chain variant. Reference: Kelley and Walker 1959; Hillier and Lieberman 2014; Kerzner 2017.
Örnek
A construction contractor lists 180 activities for a residential block project; the CPM forward + backward pass shows a 240-day critical path through excavation, foundation, columns, slabs and finishing, and exposes 35 days of total slack on the parallel landscaping chain — the planner now knows which delay risks matter.