Back to Basics: Understanding task dependencies – Microsoft Project
In the real world you will rarely find start to finish relationships, everywhere, in books and websites you will find the guard example but, I have included 2. Can any help in me in illustrating any practical Example of two activities having Start to Finish Relationship (SF). I am confusing it with Finish to. PMP® aspirants find Finish to start (FS) relationship easier to understand and practice with but the other An example from PMBOK® only.
Project offers four kinds of task dependencies: First, let's talk about finish-to-start FS dependencies. This is the most common type of dependency and is the default type of dependency that Project uses.
In a finish-to-start dependency, the second task in the relationship can't begin until the first task finishes. So, for example, if you were planning a project to make a wedding cake, you might use a finish-to-start dependency between the "Bake cake" and "Decorate cake" tasks. When the "Bake cake" task is finished, the "Decorate cake" task begins.
4 Types of logical Relationships or Dependencies in a Project Schedule
Start-to-start SS dependencies are used when the second task in the relationship can't begin until after the first task in the relationship begins. Start-to-start dependencies don't require that both tasks start at the same time. They simply require that the first task has begun, in order for the second task to begin.
- Understanding Task Dependencies in Project Management
- Start to Finish Relationships – to use them, or not?
- Start to finish (SF) Relationship Example
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.
The Start to Finish relationship is pulling on its predecessor. What is also interesting is that if you look at the Total Float value for the Run Generator activity, it only shows 2 days. Why only two days? To answer that question we have to go under the hood and look at a sample of the forward and backward pass process on our Start to Finish activity.
4 types of logical relationships or dependencies
Now you might be wondering why B is apparently showing a 2 day float on the late dates, but a 3 day float on the early dates the delta between the early and late dates is the total float. If activity is turned off any later than that, it will in this example become critical. The float of activity B then, is always equal to the duration of its SF predecessor A. Moving on… Ok, pass the Excedrin and enough of this backward number-crunching stuff. It just makes me glad I was borne in the computer age.
Imagine doing this stuff manually like they did in the project rooms of yesteryear. Indeed I wonder if they used SF at all.
All we need to know these days is that Primavera P6 is doing it right. So what has all this bought us in terms of our power lines and generator scenario?
If the power line guys are really dragging and the planned finish date starts slipping, you are going to see increases in the at complete duration of the Run Generator activity and variance on its finish date if a baseline has been taken.
Technically it is correct. But what it buys us, versus the headache we get trying to figure out how it affects the critical path is questionable. When the power lines go live, we kill the generator and the LOE finishes.
I was planning a large number of long duration training delivery tasks that represented many one day classes over a period of weeks. The training was for two different business groups, one of which needed to finish before the other.
Therefore rather than create two consecutive activities for every class and group, and then tie a finish milestone to the back of each one, I simply used a SF relationship and then put a lag on it.
I used a SF relationship because the milestone was a finish milestone. I thus took the path that seemed most compliant with the generally accepted scheduling best practice guidelines.
tasks - "Start to finish" dependency example? - Project Management Stack Exchange
It kept a lot of unnecessary detail out of the schedule, but still gave a provable date of completion that would slip appropriately if the start of the training got delayed. Summary and Conclusions Most examples of start to finish relationships always seem to refer to non-deliverable type activities.
Shift changes and even running generators are ongoing, non-deliverable items. There is almost always an easier and more understandable way to model what SF is supposed to be modeling, particularly when using a tool as flexible as Primavera P6.