Classifying dependency types

Dependencies differ not only by who controls them but also by how tasks are related in time. Understanding these relationships helps product teams plan in a logical, predictable order rather than relying on intuition. When each dependency type is clear, scheduling conflicts can be reduced and collaboration becomes easier.

There are four main relationships between tasks:

• Finish-to-Start: one task must finish before another can begin, for instance, development completing before testing starts.
• Start-to-Start: both tasks can start once the first begins, such as content writing beginning after the first interface screens are designed.
• Finish-to-Finish: one task must finish before another can close, for example, localization ending only after copywriting is finalized.
• Start-to-Finish: one task cannot finish until another starts, such as a night support shift ending when the morning one begins.

Recognizing these types helps teams identify their critical path, the sequence of essential steps that defines the minimum time needed to deliver a product. Including this logic in the product specification ensures that dependencies are visible, timelines are realistic, and cross-team coordination becomes easier to track.