Gantt Chart Dependencies
What are Predecessors and Successors?
With wacky terms like Finish to Finish (FS) and Start to Finish (SF), Gantt Charts sound more intimidating than they really are. However, once you learn to become comfortable with Gantt Charts and start adopting them for your own projects and teams, you’ll start to see the value in them. Let’s go over the four types of Gantt Chart Dependencies and what they mean.
- Predecessor – The task that comes before the successor.
- Successor – The task that depends on the predecessor.
While the successor task usually can’t be started until the predecessor task is complete, this isn’t always the case. First, we’ll define the 4 different forms of predecessor-successor relationships later.
Here are some simple examples of a predecessor-successor pairs:
- Predecessor: First, Wash dishes
Successor: Then, dry dishes - Predecessor: First, start the car
Successor: Next, drive to the supermarket
What are the 4 Gantt Chart Dependencies?
There are four types of Gantt Chart dependencies. The first letter represents the predecessor’s status, while the second latter represents the successor’s status.
- Finish to Start (FS) – Predecessor must finish before sucessor can start.
- Start to Start (SS) – Predecessor must finish before successor can start.
- Finish to Finish (FF) – Predecessor must finish before successor can finish.
- Start to Finish (SF) – Predecessor must start before successor can finish
Examples of Each Dependency Type
Here are some examples of each dependency type:
- Finish to Start (FS) – Predecessor must finish before successor can start.
You must finish turning on your car (F) before you can start driving (S). - Start to Start (SS) – Predecessor must finish before successor can start.
In order to start cooking dinner, you will have to already have started marinating the steak. It doesn’t matter if you marinate the steak for 15 minutes or 24 hours, but the you want to start marinating the steak (S) before you even start cooking the meal (S). - Finish to Finish (FF) – Predecessor must finish before successor can finish.
If you are prepping a three-course meal, and the main dish is steak, you must finish cooking the steak (F) before you can finish prepping the meal (F). - Start to Finish (SF) – Predecessor must start before successor can finish.
Even if you only have up 5 out of 40 total ornaments, there’s no fixed rule to when a tree has “enough” ornaments. As long as you start decorating the tree, it’s considered “decorated.” You have to start hanging up ornaments (S) before you can finish decorating the living room (F).
