When you’re managing a project, the knowledge and utilization of task relationships or dependencies are crucial for keeping everything on track. One important type of dependency to understand is the start to start relationship.
This is when the initiation of one task relies on another task starting first. Although not as common as a finish-to-start dependency, start-to-start can be a key component in your project schedule and activity network diagrams.
In this post, we’ll explore this unique relationship in-depth. You’ll learn what a start-to-start dependency is, see examples, and understand how it differs from other types of task relationships.
This knowledge will ensure you can leverage start-to-start to optimize your project timelines as well as provide key insights on project schedule management if you are preparing for the PMP certification exam.
What are Task Dependencies in Project Management
To understand the start to start relationship in project management, you need to first of all understand the concept of task dependencies.
Task dependencies refer to the interconnected relationships between activities and tasks within a project which determine the sequence in which work must be performed based on logical or technical precedence.
Task dependencies impact project scheduling as some tasks rely on other tasks being started or completed first before they can begin. Without mapping these crucial dependencies, you run the risk of delays, cost overruns, and other issues.
As a project manager, you need to identify and understand the task dependencies so you can optimize workflow. This allows you to create a realistic schedule that aligns task execution with the availability of resources, technology constraints, and project objectives.
By leveraging tools like Gantt charts and network diagrams, you can effectively map dependencies and manage the timing of all your project activities.
Four Types of Task Dependencies in Project Management
There are four main types of task dependencies or relationships that you may encounter during project scheduling. These are:
1. Finish-to-start (FS) Relationship/Dependency
The finish-to-start relationship is the most common of the task dependencies. It specifies a relationship between two tasks A and B such that Task B cannot start until Task A is fully complete.
This ensures proper sequencing so that initial work is done before subsequent tasks begin. FS dependencies are useful when tasks build directly upon each other in a sequential workflow.
2. Finish-to-finish (FF) Relationship/Dependency
With a finish-to-finish dependency, Task B cannot be completed until Task A is also finished.
However, both A and B can be performed concurrently for a period before their succession is required which allows some scheduling flexibility but still enforces a mandatory order for task endings.
Finish-to-finish is helpful when tasks are independent but deliverables must be organized sequentially.
3. Start-to-start (SS) Relationship/Dependency
The start-to-start relationship specifies that Task B cannot start until Task A starts. Once Task A begins, Task B can also be worked on simultaneously. This enables parallel efficiencies when predecessor initiation is required.
Start-to-start relationships are useful when concurrent tasks require coordinated launches but can be executed independently otherwise.
4. Start-to-finish (SF) Relationship/Dependency
Finally, in a start-to-finish dependency, Task B cannot end until Task A begins. The start of Task A triggers the completion of Task B. This is the least common type of task dependency and is rarely used.
Start-to-finish only applies to scenarios where predecessor commencement directly impacts and enables successor wrap-up.
What is a Start to Start Relationship in Project Management?
A start-to-start relationship is a specific type of task dependency in project management that establishes that Task B (the successor) cannot start until Task A (the predecessor) has also started.
The key is that while Task A does not have to be completed for Task B to begin, the initiation of Task A is required to trigger the start of Task B. This allows the two tasks to be executed simultaneously and in parallel for a period of time.
Start-to-start dependencies promote workflow efficiencies because certain activities can be performed concurrently rather than sequentially.
However, the predecessor task must commence first before resource allocation to the successor can begin. This ensures proper order and coordination.
When managing a project, be aware that start-to-start relationships require careful project planning to get the timing right.
Use tools like Gantt charts and network diagrams to map these dependencies and align all interrelated task start dates. Adjusting activity time estimates and durations can help fine-tune the schedule.
Start-to-Start Relationship Example
Let’s look at a simple start-to-start dependency example for a house construction project:
- Task A – Pouring the concrete foundation
- Task B – Framing the walls
Here, the framing work of Task B cannot begin until the concrete pouring of Task A has started. This ensures the proper sequence, as the foundation must be laid before walls can be framed.
However, once the contractor breaks ground on pouring concrete, the framing subcontractor can simultaneously begin building walls.
The commencement of the predecessor (Task A) triggers the initiation of the successor (Task B), and both tasks can then proceed in parallel for a period until the foundation is set.
This is an efficient use of start-to-start because it allows overlapping task execution rather than forcing entirely sequential work. The relationship enables the overall project timeline to be condensed.
Difference Between Start to Start and Finish to Start Relationships in Project Management
The start-to-start (SS) and finish-to-start (FS) dependencies are two common types of predecessor-successor task relationships. While both link the initiation of Task B to Task A, there are some key differences between these dependencies:
Timing of Tasks
With SS, Task B can begin when Task A begins. The two tasks proceed simultaneously for a period. In contrast, FS means Task B can only start once Task A fully completes. This enforces strictly sequential timing.
Task Concurrency
An SS relationship allows for partial concurrency and parallel work such that overlapping task execution is possible. But FS means no concurrency – the tasks must happen consecutively.
Scheduling Flexibility
SS gives more flexibility to adjust start dates and task timing while FS is more restrictive since successors cannot start until predecessors finalize.
Risk Management
SS may enable better risk mitigation since delays in Task A impact both tasks. With FS, a delay in A cascades down to B.
Complexity
FS is simpler to schedule and manage as SS requires more coordination between tasks and resources.
Conclusion
Understanding start-to-start dependencies is key for optimizing your project workflow. This unique task relationship enables greater flexibility through concurrent execution.
While not as common as finish-to-start, start-to-start plays an important role in streamlining project timelines and applying this knowledge will help you achieve maximum efficiency in your projects.
