Gantt Chart Excel Template - Task Dependencies

Understanding Task Dependencies

Everything and everyone is dependent on some other person or thing.

Dependencies are any tasks or activities that are either dependent on a previous completion of a task or on which a task is dependent on. It is a simple relationship between two two or more tasks in a project.

Whenever there’s a project, expect a dependency.

Gantt Chart Dependencies
Task Dependencies in Gantt Chart Excel

Definition of Task Dependency

Task Dependency is a relationship in which a task or milestone relies on other tasks to be performed before it can be performed. This is also referred to as a logical relationship. A logical relationship can be a dependency between project tasks or between tasks and milestones.

Understanding task dependency is a key element in project management. It does not matter how good a project schedule is, if critical dependencies associated with the project are not included in the description of the effort, they represent considerable risk to delivering project value.

Effective project management begins with the end in mind. The goal of a project is always successful completion.

Setting task dependencies between tasks is the most powerful feature of Gantt Excel. The in-built auto-scheduling automation of the template is able to update the dates of tasks based on changes that are made to its dependent tasks. Gantt Chart Excel is the only Gantt chart excel template with task dependencies.

Gantt Excel gives you the ability to visualize and manage task dependencies

Gantt Chart Excel

Gantt Excel gives you the ability to see every step of your project from beginning to end.
Our Gantt Chart Excel software lets you visualize every project step.
You can create tasks and link them using dependencies, and then track their progress against deadlines and milestones.

Types of Task Dependencies

It is important to understand the types of task dependencies that can be used in Gantt Excel.

4 types of task dependencies are supported in Gantt Excel

    1. Finish-to-Start (FS)
    2. Start-to-Start (SS)
    3. Finish-to-Finish (FF)
    4. Start-to-Finish (SF)

Finish-to-Start (FS)

This is the most common and logical type of dependency in project management and the real world. In this scenario, the predecessor task must finish before the successor can start.

It follows the natural flow and progression from one task to another. Task A must finish in order for Task B to start.

This dependency means that if there are 2 tasks TASK A and B, the dependent task (B) cannot begin until the task that it depends (A) on is complete… In other words, if TASK A is delayed by a day, then B will also be delayed and will begin a day later.
Example: If you are building the foundation for your house and you have two tasks, “Excavate” and “Pour concrete,” the “Pour concrete” task cannot begin until the “Excavate” task is complete


Start-to-Start (SS)

The “Start to Start” dependency says that a task cannot start before the predecessor task starts. This dependency means that if there are 2 tasks TASK A and B, Task B can’t start until Task A starts. They don’t have to start at the same time: Task B can begin any time after Task A begins.
Example: To save time, you want to level concrete at one end of the foundation while it is still being poured at the other end. But Level concrete (B) can’t start until Pour concrete (A) has also started.


Finish-to-Finish (FF)

In this case, a task cannot end before the predecessor task ends. This dependency means that if there are 2 tasks TASK A and B, Task B can’t finish until Task A is completed. They don’t have to end at the same time: Task B can end anytime after Task A ends.

Example: Your team is adding the wiring to the building and inspecting it at the same time. Until Add wiring (A) gets done, you won’t be able to finish Inspect electrical (B).


Start-to-Finish (SF)

One peculiar dependency, which is rarely used, is “start to finish”. In this case, the predecessor task must start before the successor task can finish. Task B can’t finish until Task A begins. Task B can finish any time after Task A begins. This type of link is rarely used.
Example: The wooden window frames for your house are built off-site. You can’t finish Assemble windows (B) until Window frame delivery (A) begins.


As a rule of thumb, a good practice is to stick with the common Finish to Start dependency or else you run into the risk of creating a very confusing gantt chart.

How to Add Dependencies in Gantt Excel

  1. Identify All Task Dependencies within the Project
    The good thing about using a gantt chart tool like Gantt Excel is that it brings a lot of dependencies to surface. Ideally, you’ll want to think through all possible dependencies before creating a workflow.

    You may need to divide work into smaller tasks and subtasks as necessary so work can continue moving across the project at a uniform pace. 

    Sometimes it is overwhelming to manage task dependencies. But with brainstorming and identifying the flow of tasks, a project manager can mitigate the chances of project mishaps.

  2. Stack Tasks
    Its good practice to stack the dependent tasks on top of each other in the order in which they should be completed. The predecessor task should ideally be placed on top and the successor task below.

    Gantt Excel allows you to move tasks up and down easily.

  3. Set Dependencies
    Task dependencies can be easily set in Gantt Excel. You have to just double click a task to set task dependencies. Please watch the video tutorial below to set task dependencies.

This video tutorial will show you how to set task dependencies in Gantt Excel

Types of Dependencies

There are different types of dependencies in project management that can be categorized in many ways depending on relationships, conditions, and other factors.

Causal Dependencies 
These dependencies are found in the natural flow of tasks within a project. For example, to bake bread you need to first buy the ingredients, then mix them together, then put it in a oven and finally wait for it to bake. Each task is dependent on the completion of the previous and avoiding one step or task in the process will lead to a failed project.

Resourced Based Dependencies
These are based on constraints and have no causal dependency. Meaning, if all resources are present, all tasks and activities can be completed together. For example, within technical user stories, there could be internal constraints with lack of skills of not understanding technical terms or processes.

Preferential Dependencies
These are dependencies determined by best protocols, practices, and preferred processes. They are institutionalized to focus on the quality of the product. For example, when painting the interior of a house, the order in which the rooms and walls are painted is chosen based on a various factors such as the furniture removal, current needs and preferences.

Cross-Team Dependencies
In larger companies, cross-team dependencies pose a serious challenge. This dependency tends to exist when two or more teams are needed for the completion of a project.

External Dependencies 
These dependencies are outside the control of project managers or teams and rely on 3rd parties or outside vendors for completion.

Lead and Lag times - Space tasks out with a predefined lag or lead

Lead and lag are two terms associated with the task relationships that may occur between two or more tasks. Lead and lag are both used in the development of the project schedule.

Lag time is a delay between tasks that have a dependency. This time interval can be set between dependent tasks to allow for required delays. For example, in a construction project, you need to let the foundations set before building the walls. In this case, lag time should be set for concrete to set. A successor task can only start once the defined lag time (specified in days) has elapsed.

Lag is the delay of a successor activity.

Lead time is overlap between tasks that have a dependency. For example, if a task can start when its predecessor is half finished, you can specify a finish-to-start dependency with a lead time for the successor task. You enter lead time as a negative value.

Lead is the acceleration of a successor activity.

Predecessor and Successor Tasks - Definition

Predecessor tasks and Successor tasks are two types of dependent tasks that belong to one and the same project or process and that are performed under dependency rules. A predecessor task determines the start or finish date of its successor task.

Both types are available in any work breakdown structure that includes dependent activities. Dependency rules between tasks determine which of the tasks are predecessors and which ones are successors. Graphically it can be presented as a tree-like structure in which every higher level is the successor of its lower level, and vice-versa – every lower level is the predecessor of its higher level.

Essentially, the dependency between tasks and sub-tasks is the predecessor-successor relationships. Such relationships are used in various project management methodologies.

You can view our Gantt Chart tutorial by clicking on the link below.

Gantt Chart Excel

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