What Is a Blocker?
A blocker is an obstacle that stops the team from making progress on a work item. In the PMBOK Guide, 8th Edition, the term is used synonymously with impediment.
In Practice
A work item is “blocked” when it cannot advance until something outside the team’s immediate control is resolved — a dependency, a decision, missing information or access. Teams mark blocked items visibly (for example on the task board), escalate them promptly, and often swarm to clear high-priority blockers. Tracking how long items stay blocked reveals systemic bottlenecks.
PMBOK 8 Context
Identifying and removing blockers supports the Team and Project Work performance domains and the principle of enabling flow and value delivery in the PMBOK Guide, 8th Edition.
FAQ
Is a blocker the same as an impediment? Yes — the 8th Edition treats them as synonyms.
What should a team do with a blocker? Make it visible, escalate it, and remove it as fast as possible; limit starting new work while critical items are blocked.
Author: Tom, PMP-certified since 2004. Last updated: July 2026. Aligned with the PMBOK Guide, 8th Edition.