What is a start to start relationship?

Start-to-Start is a logical relationship that states that for one project to begin, another must also be underway. For example, the writing of a business proposal must have begun in order for editing of the proposal to take place. It is a correlation between two or more projects in which the initiation of one project depends upon when another project is begun. This is a concept that is often used by Project Management to coordinate resources and to best utilize the company’s time and financial assets.
Start-to-Start procedures are used to minimize downtime between projects and thereby maximize productivity. Also, using this methodology, Project Management has the ability to shuffle talented individuals between one project and another without compromising the integrity of either project. The advantages of using a Start-to-Start technique extend beyond Project Management to benefit the company as a whole. Instead of waiting for one project to reach its completion before beginning another, simultaneously utilizing necessary resources cuts costs and maximizing employee productivity. Given these benefits, it is not hard to understand why Start-to-Start is used to successfully.

This term is defined in the 3rd and the 4th edition of the PMBOK.

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. 

This blog post 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

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 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.

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

Conclusion

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.

Task dependencies are something which you will likely be familiar with if you are working within projects and using Microsoft Project or Primavera P6. There are however some which are less common than others and therefore may appear more complicated.

Dependency types are not difficult to understand however a good explanation is often required to fully realize the meaning. Simply put, task dependencies refer to the relationship held between each task within a project.

Within this article I will talk you through the meaning behind Start to Start dependencies, one of the four dependency types, using industry examples to help explain how it can be used.

See also these related articles:

Start to Start dependency: What does it really mean?

Start-to-Start dependency is one of the less common task dependencies therefore you may not be as familiar with it and that may be why you have found yourself here reading this article. Not to worry, I can help!

A Start-to-Start (or SS) dependency means that a successor activity cannot begin before its predecessor has started. They do not however have to start at the same time. These dependencies are common within projects which require their tasks to run parallel to one another.

Why is it called “Start-to-Start”?

Simple.

Using every-day language to describe this type of dependency, it would sound like this:

“Task B can only begin once Task A has started”.

Start-to-Start task dependency examples:

There may be times when you are required to schedule Start-to-Start task dependencies within your own projects. The following examples will help you recognize how and when this type of dependency can be used:

Example 1: Decorating

For this example imagine you are overseeing the decoration of two rooms in a house. One room is to be painted, the other is to have wallpaper hung. You have a specific start date in mind for this project and you will have both a painter and a decorator available to paint and hang wallpaper at the same time; ensuring they are working alongside one another to guarantee a short project duration. There are two tasks required in this project.

• Task 1: Paint room one
• Task 2: Hang wallpaper in room two

As there is a specific project start-date, both tasks are required to begin on the same day and therefore one cannot begin without the other. As the successor cannot start until its predecessor has, even if they are starting at the same time, this scenario is an example of a Start-to-Start dependency type.

Example 2: Construction

Imagine you are planning the work on a construction site and have to organise the external decoration of the buildings. There are two tasks required for this.

• Task 1: Assemble scaffolding
• Task 2: Paint exterior

In order to begin painting the building, there must be assembled scaffolding in place which can be used. The task “paint exterior” therefore cannot begin until the task “assemble scaffolding” has been started. This is an example of a Start-to-Start task dependency as task 2 can only begin once task 1 has started.

Example 3: IT (Load testing in IT implementations)

Imagine a company is in the process of rolling out a new SAP system that is going to be used in all of their global locations.

Before the system goes live, it is standard protocol to perform a load test (or stress test) in order to see if the system can handle the actual transaction volume. Before the actual load test can start, it is important to have the monitoring processes set up and running in order to measure the transaction performance.

This is therefore an example of a Start-to-Start dependency because load testing should not start until system monitoring has begun. The corresponding tasks are:

• Task 1: Enable system monitoring
• Task 2: Begin load testing