MS Project’s dependency types and how to establish them

Virtually all projects, regardless of size or complexity, that involve interrelated tasks, require establishing dependencies. They help in sequencing tasks, managing resources efficiently, and ensuring a smooth flow of work. Understanding and effectively managing dependencies is crucial for project success.

Microsoft Project is well-known among experienced project managers as a tool that offers a comprehensive suite of tools to work with dependencies. Lets’ delve into the intricacies of MS Project dependencies, focusing on their types, and how they can be meticulously managed within the software.

Is MS Project the best tool to work with dependencies?

Microsoft Project stands out as one of the top tools for handling dependencies, particularly in complex or large-scale projects where meticulous project scheduling and resource management are paramount. The program supports all main types of dependencies, allowing you to configure them according to your project’s needs.

As a manager, you can reschedule tasks when sequencing or duration impacts resource allocation and workload. It’s worth noting that while linking tasks is straightforward, mastering the intricacies of managing dependencies in complex projects may take some time to develop this skill. For a more user-friendly and intuitive alternative to MS Project, check this list.

MS Project dependency types

There are four main types of task dependencies, each affecting the project schedule in different ways. Let’s take two tasks: task 1 and task 2 and go through each type and examples to understand them better.

1.Finish-to-Start (marked as FS in Project)

This is the most commonly seen dependency type. It is when a “task 1” cannot start until a “task 2” has finished. We can find plenty of examples of these dependencies in construction and in many other industries. For example, the task of “laying the foundation” must be completed before “erecting the walls” can begin. Then, installing windows can’t happen before you have walls, and so on. These tasks are clearly interrelated and should be completed in specific order, one after another.

2. Start-to-Start (marked as SS in Project)

With this type of dependency, a “task 2” cannot start until “task 1” has started. But then both tasks can proceed concurrently. For example, in software development, you can’t do code review before you start writing code itself. However,both activities can occur simultaneously once both have started.

3. Finish-to-Finish (marked as FF in Project)

In this scenario a “task 2” cannot finish until “task 1” has finished. Although this is not the most widely used type, we can still encounter examples in different industries. An example might be in event planning, where “cleanup operations” cannot be completed until “event activities” have concluded. Both tasks might be underway at the same time, but the cleanup cannot fully finish until all event activities have ended.

4. Start-to-Finish (marked as SF in Project)

Finally, this is the least common dependency. It indicates that a “task 1” cannot finish until “task 2” has started. A real-life example could involve an IT system upgrade, where the old system cannot be taken offline until the new system is up and running. This ensures a seamless transition with minimal downtime.

How to link tasks in MS Project

Open Gantt chart view with task list

Head over to the Gantt Chart view to see your list of tasks along with it on the right side. With this view you’ll find it easier to see and understand how exactly linking tasks affects your project timeline.

Select the tasks you need to link

Locate the task list and click on the task you want to link. To select multiple tasks that are next to each other, hold down the “Shift” key and click on the last task you want to link. For non-adjacent tasks, hold down the “Ctrl” key and click on each task you wish to link.

Link the tasks

Once you’ve selected the tasks, go to the “Task” tab on the Ribbon. Click on the “Link the selected tasks” button (it looks like a chain link). This action will link the tasks with a standard Finish-to-Start dependency by default. As we’ve already seen, that means the first task must finish before the second task can start.

Change dependency types

If you need a different type of dependency (Start-to-Start, Finish-to-Finish, or Start-to-Finish), first link the tasks as described in the previous paragraph. Then, double-click on the arrow connecting the tasks on the Gantt chart or go to the “Task Information” dialog box for one of the tasks.

Switch to the “Predecessors” tab, where you’ll see the linked task listed. You can change the type of link in the “Type” column, selecting FS (Finish-to-Start), SS (Start-to-Start), FF (Finish-to-Finish), or SF (Start-to-Finish) from the dropdown menu. That’s it.

Use the “Predecessor” column

It is also possible to link tasks in the “Predecessors” column. Remaining in the same “Gantt chart” view, find the “Predecessors” column in your task list. If it’s not visible, add it by right-clicking on a column header, selecting “Insert Column,” and then choosing “Predecessors.”

For each task, enter the ID number of its predecessor task in the “Predecessors” column. If a task has multiple predecessors, separate their ID numbers with commas.

The default type is also Finish-to-Start, but you can change this by typing the abbreviation (FS, SS, FF, SF) next to the predecessor ID in the “Predecessors” column.

How to configure links

Lag and lead times in Microsoft Project are essential concepts for accurately scheduling tasks within a project. They represent the time delay or advancement between tasks.

What is “lag” and “lead” in Microsoft Project?

Lag Time is a delay between tasks that have a dependency. For example, if you have two tasks, “task 1” and “task 2”, where “task 2” cannot start until “task 1” has been completed, you might add a lag time to ensure that “task 2” starts a certain amount of time after “task 1” has finished. This is useful when you need to account for waiting periods or drying times in projects.

Lead Time allows a successor task to start before the predecessor task has finished. This is used when tasks can overlap. It helps to shorten the overall project duration. For example, if “task 2” can start while “task 1” is still in its final stages, you would set a lead time on “Task 2”.

How to set “lag” and “lead” in Microsoft Project?

Complete all the steps required to connect tasks with corresponding dependencies.

Then, double-click on the link line between the tasks in the “Gantt Chart” view, or open the “Task Information” dialog for the successor task and go to the “Predecessors” tab.

Here, you can enter lag or lead time. For lag time, you have to enter a positive value (e.g., 2d for two days of lag). For lead time, it should be a negative value that indicates the overlap (e.g., -1d for one day of lead time).

Tips

1. Always review the logical flow of tasks after linking them to ensure it matches the intended project execution plan.
2. Use the “Task Information” dialog box to get more detailed options for setting up and adjusting task dependencies.
3. Don’t forget to regularly update and adjust task dependencies as your project progresses to reflect any changes in your project’s scope or timeline.

By following these steps, you’ll be able to effectively manage task sequences and dependencies in Microsoft Project and guarantee that your project stays on track.