When should I use LEAD in MS Project?

Last week, I answered the question of when to use lag. Now I’m going to describe its counterpart – lead.

Lead is the amount of time a successor task can overlap its predecessor. In other words, how soon can a task begin before its predecessor completely finishes? My two-word definition for lead is overlapped tasks. Please note that I’m referring only to tasks that have a relationship between each other.

For instance, let’s say that I am a programmer and one my tasks is Develop code. I also have a task for unit testing my own work, Test code. Would you agree that I can’t actually test the code unless I develop the code? Therefore, I should use a finish-to-start relationship. However, I am asked to shorten the duration of my project. One of my options is to simply start testing before I am completely done developing. Maybe I will start testing two days before I am scheduled to finish developing. If that’s the case, I will apply two days of lead on that link.

By the way, if you’re looking for the lead field in MS Project, you won’t find it. You have to put a negative number in the lag field.

And lastly, just as I stated for lag, the same applies here — no dependencies, no lead.