A task from whole number of tasks of a project that upon completion is followed by another task of project. Predecessor task starting time/date and finishing time/date depends upon its successor tasks, simply we can say that predecessor task has a dependent relationship with its successor task. In other words we can say that a predecessor task is a task whose start/finish date/time determines the start/finish date/time of its successor task. Predecessor task is the task/activity that must be started/finished before another task (successor task) or milestone could performed.
A task from whole number of tasks of a project that cannot start until its prerequisites task or tasks are started or finished. Successor task starting time/date depends upon its predecessor tasks, simply we can say that successor task has a dependent relationship with its predecessor task. Successor task is a task whose start/finish date/time depends upon its predecessor task.
Relationship between Predecessor Task and Successor Task
There are different types of logical relationship exist among tasks of a real life project e.g. two starts cannot starts/finish at the same time, on completion of one task another task could be performed, two tasks should starts simultaneously, two tasks should finishes simultaneously etc. There are four types of dependency relationships exist between tasks:
Task 1 must be finished before task 2 could start. This type of relationship can easily be created between tasks and most commonly used relationship between tasks in the project.
Both tasks i.e. Task 1 and Task 2 must start simultaneously.
Both tasks i.e. Task 1 and Task 2 must finish simultaneously.
Task 2 could not finished until Task 1 starts. This is not common relationship between tasks in real life projects.
Predecessor and Successor Relationship in Project Planning
Multiple studies shows that around 65% projects failed due to poor planning, so project planning is backbone for timely and successful completion of project. Project manager spends maximum time in planning phase of project because “if you fail to plan, you plan to fail”. In planning phase all tasks of the projects are identified, tasks are divided into more manageable tasks. Logical relationships between tasks are identified in planning phase of project. Keeping in view of logical dependency between tasks, tasks are scheduled and linked maintaining logical dependency.
For example in construction of power plant, equipment’s could not installed till construction/foundations of equipemts are completed. Similarly equipments commissioning could not starts before installation is completed. So the relationship between construction and equipments installations is finish to start relationship. Similarly installations of equipments and commissioning have finish to start relationship. While conceiving of plant idea and project planning having start to start relationship. Usually commissioning activities of power plants lap on 24hours (8hours/shift). Taking charge from previous shift also having finish to start relationship.
Benefits of Good Predecessor and Successor Relationship in Planning
- Effective schedule development
- Efficient resource allocation
- Efficient usage of resources acquired for project
- Efficient usage of time
- Effectively managing activity sequencing
- Easy tracking of project progress