Dependency (project management) - Wikipedia
Some tasks need to start or finish at the same time, while other tasks can't The next type of dependency is the start-to-start relationship (SS). This article describes finish to start relationship (precedence diagramming on Project Dependencies – What are Project Dependencies and 4 Types of Project. There are four types of task dependencies, and each one has its own specific In this relationship, task B cannot start until task A finishes.
They simply require that the first task has begun, in order for the second task to begin. Going back to the wedding cake example, let's say you had planned to make the icing for the cake while the cake is baking in the oven.
4 types of logical relationships or dependencies
You can't start making the icing until the cake has started baking, so you might use a start-to-start dependency between the "Bake cake" and "Make icing" tasks. If one of your tasks can't finish until another one finishes, you can use a finish-to-finish FF dependency between them.
Finish-to-finish dependencies don't require that both tasks be completed simultaneously. They simply require that the first task be finished, in order for the second task to finish.
Types of task links
The second task can finish any time after the first task finishes. In our wedding cake example, let's say there are some finishing touches to the decorations that you can't finish until the cake is delivered.
You can use a finish-to-finish dependency between the "Decorate cake" and "Deliver cake" tasks. When the "Decorate cake" task is finished, then the "Deliver cake" task can be completed. Finally, the start-to-finish SF dependency is a little tricky.
When you use this type of dependency, you are saying that the second task in the relationship can't finish until the first task starts. However, the second task can finish any time after the first task starts. Going back to our wedding cake example, let's say you have a task for billing the customer. It begins when the customer requests the cake, but it can't be completed until after the cake delivery has begun.
Back to Basics: Understanding task dependencies – Microsoft Project
You can use a start-to-finish dependency between the "Deliver cake" and "Bill customer" tasks, so that when the "Deliver cake" task has begun, it is okay for the "Bill customer" task to finish. Whenever possible, the FS logical relationship should be used. If other types of relationships are used, they shall be used sparingly and with full understanding of how the relationships have been implemented in the scheduling software being used.Dependencies in Project Management — Episode 4
Ideally, the sequence of all activities will be defined in such a way that the start of every activity has a logical relationship from a predecessor and the finish of every activity has a logical relationship to a successor".
Microsoft recommends to use SF dependency for just-in-time scheduling. There are three kinds of dependencies with respect to the reason for the existence of dependency: Causal logical It is impossible to edit a text before it is written It is illogical to pour concrete before you dig the foundations of a building Resource constraints It is logically possible to paint four walls in a room simultaneously but there is only one painter Discretionary preferential I want to paint the living room before painting the dining room, although I could do it the other way round, too Early critical path -derived schedules often reflected only on causal logical or discretionary preferential dependencies because the assumption was that resources would be available or could be made available.
Understanding Task Dependencies in Project Management
Since at least the mids, competent project managers and schedulers have recognized that schedules must be based on resource availability. The critical chain method necessitates taking into account resource constraint-derived dependencies as well.
- 4 Types of logical Relationships or Dependencies in a Project Schedule
- Back to Basics: Understanding task dependencies
- Dependency (project management)
Leads and Lags[ edit ] Dependencies can be modified by leads, and lags. Both leads and lags can be applied to all 4 types of dependencies. PMBOK defines lag as "the amount of time whereby a successor activity will be delayed with respect to a predecessor activity".