Leads and Lags

Lead is advancing an activity and Lag is delaying an activity. This technique is used while planning when we are constructing the network diagram using by considering the dependencies. Also this technique is used during Monitoring and Controlling to bring the project on track by adjusting Lead and Lag.

Suppose you want to reach office 9 in the morning. Every day it may take about an hour to reach. So usually you start at 8 in the morning. But let us you know that tomorrow there is a blockage of road due to some rally in the usual route, you need to take alternative route. But it takes more time. So what you do? Instead of starting at 8 in the morning, you plan to start at may be 7.30 in the morning. This half an hour is called lead. You are advancing an activity.

Lag is waiting period between two activities. Once you construct ground floor, you need to wait for two days before starting the first floor. This waiting period which is 2 days is called lag.

Lead and Lag technique is used under processes like Sequence Activities, Develop Schedule and Control Schedule processes.