Develop schedule

Develop schedule 

• Schedule network analysis – an iterative process performed until a viable schedule model is arrived at and comprises of;
  • Critical path method
  • Resource optimization techniques
  • Modeling techniques
  • Assessing the need to aggregate schedule reserves at the points of path convergence, to reduce the probability of schedule slip
  • Critical path review to detect activities of long lead times, high risk activities
  • Analysis of near critical paths

Let us consider a project with just activities, A & B. Total duration of activity ‘A’ is 12 days which comprises of 10 days of actual time required and a buffer of 2 days for contingency management. Activity ‘B’ has a duration of 6 days including the buffer. If we start ‘A’ on day 1, it can be completed on the 12th day. If we start ‘B’ on day 1, it will get over by 6th day. I can even start ‘B’ on day 7 and still complete it on day 12, without delaying the project.

For activity ‘A’;

Early start (ES) = 1, Early finish (EF) = 12

Late start (LS) = 1 and Late finish (LF) = 12

For activity ‘B’;

Early start (ES) = 1 , Early finish (EF) = 6

Late start (LS) = 7, Late finish (LF) = 12

Float is the amount of time an activity can be delayed without affecting the early start of the subsequent activity.

Float = (LS-ES) or (LF-EF)

Float for activity A = 1-1 or 12-12 = 0

Float for activity B = 7-1 or 12-6 = 6

If activity ‘A’ slips by 1 day, the project will slip by 1 day, where as even if activity ‘B’ slips by 6 days, the project will not slip.

If we connect all the activities whose float=0, that is the critical path. In the above example, activity ‘A’ is on the critical path.

Activities on the critical path cannot slip. If activity ‘A’ slips by 1 day, the project will slip by 1 day, where as even if activity ‘B’ slips by 6 days, the project will not slip.

Sometimes, there can be more than one critical path for the projects.

Critical path method – Critical path is the shortest possible time in which the project can be completed. The steps involved in determining the critical path are;

Forward pass through the network to identify the Early Start (ES), and the Early Finish (EF)

Backward pass to identify the Late Start (LS) and the Late Finish (LF)

Calculate the float for all activities on the network using the formula Float = LS-ES or LF-EF

Connect all the activities whose float = 0, and that is the critical path

Sometimes there can be multiple paths, whose float=0. That means the project has more than one critical path and will be complex to manage.

It is a good practice to track those paths whose float is very less. Technically they do not fall under ‘critical path’ but they are very close to critical path. They are also known as near critical paths.

Resource optimization

Resource leveling – Ensuring that all the resources are loaded equally. Tries to answer the question ‘With the resources available, when will the work be finished.

Resource smoothing – Resource smoothing is used when the time constraint takes priority. The objective is to complete the work by the required date while avoiding peaks and troughs of resource demand.

Leads and lags 

Leads indicates parallelism across activities. Leads compresses the schedule.

Lags denote waiting time. Lags always stretches the schedule.

Schedule compression 

Fast tracking – Is about trying to do things in parallel, which were originally scheduled sequentially

Crashing – Reducing the duration of an activity by adding more resources to the activity.