A dependency is a relationship between two things i.e. between two tasks in a plan. This relationship must be closely managed as often changes to one task will directly impact the other.
When creating a dependency link in the Gantt view there are 4 types:
- Finish to Start
- Start to Finish
- Finish to Finish
- Start to Finish
The below examples detail the effect of auto scheduling on each of these different dependency types.
Example 1 - Finish to Start
Dependency |
Auto Scheduling Off |
Slack |
Lag |
|---|---|---|---|
Finish to Start |
The dependent task (Task 1.1) can start before the preceding task (Task 1) has finished. Any slack within the plan will remain but any lag entered when creating the dependency link will not be respected. | Yes |
No |
Dependency |
Auto Scheduling On |
Slack |
Lag |
|---|---|---|---|
Finish to Start |
The dependent task (Task 1.1) cannot start before the preceding task (Task 1) has finished. Any slack within the plan will remain and any lag entered when creating the dependency link will be respected. | Yes |
Yes |
Example 2 - Start to Start
Dependency |
Auto Scheduling Off |
Slack |
Lag |
|---|---|---|---|
Start to Start |
The dependent task (Task 1.1) can start before the preceding task (Task 1) has started. Any slack within the plan will remain but any lag entered when creating the dependency link will not be respected. | Yes |
No |
Dependency |
Auto Scheduling On |
Slack |
Lag |
|---|---|---|---|
Start to Start |
The dependent task (Task 1.1) cannot start before the preceding task (Task 1) has started. Any slack within the plan will remain and any lag entered when creating the dependency link will be respected. | Yes |
Yes |
Example 3 - Finish to Finish
Dependency |
Auto Scheduling Off |
Slack |
Lag |
|---|---|---|---|
Finish to Finish |
The dependent task (Task 1.1) can finish before the preceding task (Task 1) has ended. Any slack within the plan will remain but any lag entered when creating the dependency link will not be respected. | Yes |
No |
Dependency |
Auto Scheduling On |
Slack |
Lag |
|---|---|---|---|
Finish to Finish |
The dependent task (Task 1.1) cannot finish before preceding task (Task 1) has ended but can finish after. Any slack within the plan will remain and any lag entered when creating the dependency link will be respected. | Yes |
Yes |
Example 4 - Start to Finish
Dependency |
Auto Scheduling Off |
Slack |
Lag |
|---|---|---|---|
Start to Finish |
The dependent task (Task 1.1) can finish before the preceding task (Task 1) has started. Any slack within the plan will remain but any lag entered when creating the dependency link will not be respected. | Yes |
No |
Dependency |
Auto Scheduling On |
Slack |
Lag |
|---|---|---|---|
Start to Finish |
The dependent task (Task 1.1) cannot finish before the preceding task (Task 1) has started but it could start after the preceding task has begun. Any slack within the plan will remain and any lag entered when creating the dependency link will be respected. | Yes |
Yes |
Top Tip
- All slack is removed when auto scheduling is set to On (Strict) but lag is still respected.
- Lag is the amount of time that must pass between two tasks.