In the project management planning phase, the project schedule is made keeping in view the activities dependencies. You can say, from initiating planning to closure stage, all factors are dependent on another factor in each stage. Project dependency is a curtailment based logical relationship between tasks or activities such that the initiation or completion of one task is linked with the initiation or completion of the other task.
To understand dependency constraint for activities let’s take a few examples from daily life;
- During construction of a new house, one can’t paint a wall before construction of a wall. This means the activity of painting a wall is linked to its construction unless construction completes painting can’t be done completed.
- Being a student to get a pass in the exam. It’s necessary to prepare for an exam, appear in the exam and give the correct answer to the questions. If one skips any of these activities. The event of passing the exam will not be achieved. This is an example of one activity linked with many other activities.
Types of Dependencies for Project Scheduling:
For making a project schedule, it is necessary to understand the types of activity dependencies. Most project management software link activities based on below dependency types;
S.S Dependency (Start to Start): In this relationship, both activities must start at the same time. If the start of any activity gets delayed due to any reason, the other activity will also not start.
F.F Dependency (Finish to Finish): In this relationship, both activities must end at the same time. If the end of any activity gets delayed due to any reason, the other activity also can’t be completed.
S.F Dependency (Start to Finish): In this relationship, to finish the second activity first activity has to start. If the start of the first activity gets delayed, it will delay the completion of the second activity.
There are few other categories of project dependencies such as;
Preferential Dependencies: These activities can be performed in many ways but the one which is chosen depends on best practices keeping in view the quality or shorter lead times.
Constraint-Based Dependencies: In this dependency relationship, activities completion, start, and duration is linked with the availability of resources such as skilled labor and equipment.
Dependencies between Projects:
There can be two types of dependencies between the projects.
Downstream Dependency: In this relationship, a project must have delivered something before something else can be started.
Matrix of Project Dependencies:
There are four categories of PD based on project managers’ influence and company;
In-Company, In-PD – It’s related to sequential activities that are directly linked to the project and handled by the company.
In-Company, Out-PD – It’s related to activities that are not directly from project tasks but handled by the company.
Out-Company, In-PD – It’s related to activities that are directly related to the project but handled by third party suppliers.
Out-Company, Out-PD – It’s related to factors that are not directly linked to the project and not handled by the company.