Task Dependencies

Task dependency is a relationship between two tasks in which one task is dependent on the another task. For instance, in a construction project, "Building Walls" task can only begin once the "Lay Foundation" task has already been finished. Hence, the "Building Walls" task is dependent on the "Lay Foundation" task.

What is the impact when I create dependencies?

Once you enter the task duration and dependencies between the tasks, Celoxis automatically calculates the start and finish dates for all dependent tasks. Also, when you reschedule a task, Celoxis automatically reschedules all its dependent tasks as well. Entering dependencies ensures your project plans are always accurate and consistent.

In Celoxis, you can have 4 types of dependencies :

FS - Finish to Start - The dependent task cannot begin until the task that it depends on is complete. 
SS - Start to Start -  The dependent task cannot begin until the task that it depends on begins.
FF - Finish to Finish - The dependent task cannot be completed until the task that it depends on is completed.
SF - Start to Finish -  The dependent task cannot be completed until the task that it depends on begins.

Lead and Lag Time

Lead Time: In most cases, when a task is nearing completion you may want to begin another task. For instance, 3 days prior to the construction of the walls of your home is completed, you may want to start selecting the color of the paint for the walls. So, for the ‘Select Color’ task you will select the ‘Construct Walls’ task as the predecessor and enter a lead time of 3 days. Lead time is specified as a negative number. For instance, 5[-3d] indicates a predecessor with 3 days lead time.

Lag time: Sometimes it may happen that a task cannot begin as soon as another task gets completed. It may take sometime. For instance, once you paint the walls, it may take another 2 days for the paint to dry and only then you can begin furnishing the room. In this case, you would select the "Paint Walls" as the predecessor of the "Furnish Room" task and enter a lag of 2 days. Lag time is specified as a positive number. For instance, 8[+4h] indicates a predecessor with 4 hours lag time.