start to start relationship

A start-to-start relationship is a project management dependency mainly used in developing activity-on-node network diagrams. It is not as commonplace as the finish-to-start relationship. 

In this blog post, we will discuss the start-to-start (SS) relationship in project management.

Before we move any further, let’s understand some terminology used in this blog post.

A predecessor activity comes before another activity in the schedule relationship diagram.

The following activity is known as a successor activity.

A lead is when the successor activity starts while the predecessor is not yet completed.

A lag is when there is a delay between these activities.

Lag is denoted by the “+” sign, lead is the “-” sign.

Start-to-Start Relationship

start to start 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

In this blog post, I will provide you with details of the start-to-start relationship.

According to the PMBOK Guide, “Start to Start is a Logical Relationship in which a Successor Activity cannot start until a Predecessor Activity has started.”

In simple words, the start of the successor activity depends on the start of the predecessor activity.

Representation of a Start-to-Start Activity

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

start to start

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

start to start relationship on a gantt chart

Example of a Start-to-Start Relationship

Say you are renovating a building and you need to paint a wall. For this to happen, you have to apply the prime at the same time. This is an example of a start-to-start relationship.

In another example, the leveling of concrete (successor) cannot begin until the pouring of the foundation (predecessor) begins.


The start-to-start relation is used for activity on node diagrams and is not very common. In this type of project management relationship, both activities start together.

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