Different terms about linking tasks
Perhaps you will hear other terms at your company, like
links or
task relationships, but they
all mean the same, which are the black arrows between tasks in the Gantt chart.
Why linking tasks in MS Project?
Linking tasks is
automating your schedule. You want MS Project do the calculations for you. Compare a task relationship with a formula in Excel. You use a formula in Excel when you don't want to use a Casio calculator next to your Excel file to do the calculations.
It is very important that you
consult with all possible stakeholders. Planning an entire day for 35 people might be a very good investment if you consider that one forgotten dependency can easily push your project back for months. Think of having some software installed as a precondition for other software, or on boarding or training requirements before a resource can start on your project, or business processes that need to be followed but you did not know yet.
Functional dependencies
The tasks you link should be
functional dependencies. This means that in reality a task
cannot start before another one finishes, as this would totally not make sense.
- For example, placing the roof on a building when the supporting walls have not yet been finished is physically not possible. Reviewing a document before it is written is also not the correct order.
Resource dependencies
Resource dependencies are to indicate that a task can only start when this resource finished the previous one.
- For example, because multi-tasking only works to a certain level and you can only start painting room 2 once you have finished room 1, or vice versa.

Using links for resource dependencies introduces unwanted inflexibility to your plan. Suppose that someone else just become available to paint room 2, you do not want to have a task dependency anymore, as this would keep the tasks in sequence, although the tasks could be done in parallel now. This issue is solved when we explain how to level workloads in our e-course Maturity Level 4
Resource Management. For now, it is fine to use links for resource dependencies, but we do recommend to place a note before each task where you did this (
double-click on the task > tab notes). This note (like: "I used a link for a resource dependency here") will remind you to
delete this link once you have found a new resource for the task.