Linking tasks in Microsoft Project

In my series on how to use Project as a product owner blessed with Team system, I've come to links!

Everyone that have ever used Microsoft Project soon discovers that you can link task. The first method used for most users is probably dragging the bar of one task to the bar of another task.

What happens when you do so is that the field Predecessor becomes filled in. And for the more advanced users there is also a Successor field.

• Predecessors
  The ID of tasks which affects the current task
• Successors
  The ID of tasks which are affected by the current task

When you double click the link between two tasks, the Link Task dialog box becomes visible and in this you can control the link. Let us say we have task A and task B. You can find the ID of A in Predecessors of task B

• Finish-To-Start
  The finish time of Task A affects the start time of B. This is the default link and can be translated into "The finishing of The foundation of the House controls when we can start the work with The Walls"
• Start-To-Start
  The start time of Task A affects the start time of B. This can be translated into "We cannot start testing before we've started developing".
• Finish-To-Finish
  The finish time of Task A affects the finish time of B. This can be translated into "We cannot stop testing before we've stopped developing".
• Finish-To Start
  The finish time of Task A affects the start time of B. This can be translated into "We cannot stop using the old system before we've started using the new system".

When you changed the link type you can see this in the Predecessors field: 3SF means that a task cannot start until task 3 has finished.

To make it a bit more complicated you can also add a gap. A link with a gap can read 3sf+3d. Observe that if you're using gaps you need to specify link type. Remember that all units possible on Duration is also valid on gaps, including Elapsed. And gaps can also be given in negative numbers (3SF-3d) But just to give you an example on the most common settings:

• 3FS+3d
  The task cannot start until three working days after 3 has finished.
  "Three working days after delivery, operations can start upgrading."
  
• 3SF+3d
  The task cannot finish until three working days after 3 has started.
  "We need to have the old system functual three days after the new system is operational"
  
• 3SS+3d
  The task cannot start until three working days after 3 has Started.
  "Three days after we've started developing, we can start planning for new sprint"
  
• 3FF+3d
  The task cannot finish until three working days after 3 has finished.
  "Three days after we've finished developing, we can finish testing"

But why not simply drag the tasks in the calendar and not link? I'll get back to that!