What does 'activity dependency' refer to in project scheduling?

Activity dependency in project scheduling specifically refers to the relationship between tasks where one task relies on another. This relationship is critical for determining the sequence in which tasks are to be executed and helps project managers understand how a delay in one task can affect the overall schedule.

Understanding activity dependencies is essential for effective project management because it allows the project team to identify critical paths, prioritize tasks, and allocate resources efficiently. It facilitates better planning and risk management, as project managers can foresee potential bottlenecks and take corrective actions to mitigate delays.

The other choices address important elements of project scheduling but do not define activity dependency. A list of tasks completed sequentially is a result of describing dependencies but lacks the focus on the reliance aspect. The duration refers to how long a task takes to complete, which is a separate consideration in scheduling. The overall timeline relates to the project schedule but does not encapsulate the specific relationships between individual tasks.