Types of task links - Project
In this relationship, task B cannot start until task A finishes. Once all the tasks in the project have their relationships established, the critical. Finish-to-Start relationship is straight forward as most of the tasks fall under this category. Start-to-Start and Finish-to-Finish tasks are also relatively common. Dependencies enable you to work out the optimal task order, providing the fastest route through the Predecessor must start before Successor can finish.
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. Leads and Lags[ edit ] Dependencies can be modified by leads, and lags.
- Types of task links
- Understanding Task Dependencies in Project Management
- Change a task link
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".
Back to Basics: Understanding task dependencies – Microsoft Project
When building two walls from a novel design, one might start the second wall 2 days after the first so that the second team can learn from the first. This is an example of a lag in a Start-Start relationship. In accordance to PMBOK a lead is "the amount of time whereby a successor activity can be advanced with respect to a predecessor activity For example, on a project to construct a new office building, the landscaping could be scheduled to start prior to the scheduled punch list completion.
This would be shown as a finish-to-start with two-week lead". It would be much faster and less expensive, to install the pipes first, place the concrete to actually build the wall around the pipes, and finally paint the walls. Shoring of the trench has to be done not necessarily immediately after excavation, but within certain time, otherwise the trench will collapse. 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.
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.
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.Project 2007: Changing Task Relationship Types
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.
Back to Basics: Understanding task dependencies
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.
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.