start to finish relationship

Today we will discuss start-to-finish relationships in a project network diagram. This project management dependency is not as common as a finish-to-start relationship, but knowing about it will help you develop a sound schedule network diagram.

Let’s start by understanding the terminology.

A predecessor activity will be completed before another activity, logically. 

A successor activity will be completed after another activity, logically.

A lead is when the successor activity starts before the completion of the predecessor activity. This is an advancement and is denoted by the “-” sign.

A lag is a delay between a predecessor and a successor activity. It is denoted by the “+” sign. 

Start-to-Finish Relationship

A project network diagram can have four types of dependency:

  1. Finish-to-start
  2. Finish-to-finish
  3. Start-to-finish
  4. Start-to-start

According to the PMBOK Guide, a start-to-finish (SF) relationship is “A logical relationship in which a successor activity cannot finish until a predecessor activity has started. ”

 In simple words, the finish of a successor activity is dependent on the start of the predecessor activity.

Representation of Start-to-Finish Activity

Here is how a start-to-finish relationship is shown in a network diagram.

start to finish

Here is how a start-to-finish relationship is shown on a bar or a Gantt chart.

start to finish relationship on a gantt chart

Example of Start-to-Finish Relationship

Consider a construction project where you need to move to a new house. To be able to do this, the new house needs to be already built. This is an example of a Start-to-Finish relationship.

Consider another example.

A new accounts payable system (successor) has to start before the old accounts payable system can be shut down (predecessor).

Conclusion

Start-to-finish is rarely used in developing a scheduling network diagram. The successor activity cannot finish before predecessor activities start.

Here is where this post on the start-to-finish relationship ends. Please share your experience with using it in the comments section.