← Back to BookReference

Glossary of PM Terms

Key definitions for project scheduling terminology.

Activity

A discrete piece of work with a defined start and end. The formal term for what's commonly called a 'task'. Used interchangeably in practice.

Baseline

A saved snapshot of the schedule at a point in time (usually after initial planning or approval). Used to compare current status against the original plan.

Critical Path

The longest sequence of dependent tasks in a project. It determines the minimum project duration. Any delay on the critical path delays the project.

Dependency

A logical link between tasks that defines their sequence. The most common type is Finish-to-Start: Task B cannot start until Task A finishes.

Duration

The time required to complete a task, measured in work hours or days. Duration is work time, not calendar time — it doesn't include non-working days.

Effort (Work)

The total person-hours required for a task. A 40-hour effort might have a 5-day duration with one person, or a 1-day duration with five people.

Finish-to-Finish (FF)

A dependency type where the successor cannot finish until the predecessor finishes. Both tasks can proceed in parallel.

Finish-to-Start (FS)

The most common dependency type. The successor cannot start until the predecessor finishes. The default in most PM tools.

Float (Slack)

The amount of time a task can be delayed without delaying the project's finish date. Tasks with zero float are on the critical path.

FNLT (Finish No Later Than)

A deadline constraint. In Consequent, if the calculated finish exceeds this date, the system flags a violation rather than silently blocking.

Gantt Chart

A bar chart showing tasks plotted against time. Developed by Henry Gantt around 1910, it remains the standard visualization for project schedules.

Lag

A delay added to a dependency (e.g., 'Task B starts 3 days after Task A finishes'). Consequent discourages lag in favor of explicit waiting tasks.

Milestone

A zero-duration marker representing a significant point in time: 'Contract signed', 'Phase complete'. Milestones mark events, not work.

Predecessor

A task that must happen before another task. In 'A → B', task A is the predecessor of task B.

SNET (Start No Earlier Than)

A constraint that prevents a task from being scheduled before a specific date, regardless of when its dependencies are satisfied.

Start-to-Finish (SF)

A rare dependency type where the successor cannot finish until the predecessor starts. Used in just-in-time scenarios.

Start-to-Start (SS)

A dependency type where the successor cannot start until the predecessor starts. Both tasks begin around the same time.

Successor

A task that depends on another task. In 'A → B', task B is the successor of task A.

Summary Task (Parent Task)

A task that contains child tasks. Its duration is calculated from its children. Also called a 'hammock' or 'roll-up' task.

Task

The common term for a discrete piece of work in a project. Technically 'activity' is more precise, but 'task' dominates in practice.

WBS (Work Breakdown Structure)

A hierarchical decomposition of the project into phases, deliverables, and tasks. The structure that organizes your schedule.

Waterfall

A project management methodology where work flows sequentially through defined phases. Each phase must complete before the next begins.