Microsoft Project 2007: Using Lag and Lead

In addition to using task relationship, you can modify when a relationship goes into effect using Lag and Lead options. As you create relationships, you will see the Lag box in both the Task Dependency dialog box and the Task Information dialog box. Lag and Lead time are both entered in the Lag box.

Lag Time is the amount of time you want to delay the start of the successor task.

Lead Time is the amount of time you want to give head start to the successor task. Successor task will begin partway through the work of predecessor task.

Let's see an example of using Lag and Lead. We have two tasks.
Screen 1: Shows these tasks with simple Finish to Start relationship.

Now we want to delay Task 2 by two days

Screen 2: Shows steps to add two days Lag

Screen 3: Shows the effect of adding Lag on Task 2

Similarly if you want to start task 2 partially when task 1 is complete then you add Lead time.
Lead is also known as Negative Lag.


Add -2 (negative two) in the Lag column of Task details screen (i.e. screen 2 above).

Screen 4: Shows the effect of adding Lead on task 2