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How Do We Schedule?

Scheduling noncritical tasks is important in project planning. Watch Professor Yael Grushka-Cockayne explain more.
So we’ve carried out a critical path analysis to come up with our project duration estimate and to identify which of the activities in our network, in our project, are critical. Those critical tasks have zero slack, they need to start as soon as we can and they need to finish on time. However, lets think about the noncritical tasks. When do we schedule those activities? When do we think that we would like to perform the work? Well, in the example that we had for our startup project, several of these activities are non-critical and have some slack associated with them. Let’s look at the IT project. The IT project at the earliest we said will start at zero and finish at four.
However, we know that we can postpone it to start as late as week eight. So, we have plenty of slack associated with this task. So, when should we do the work? Should we ask it to be performed or expect it to be performed, or schedule it to be performed as soon as we can, or should we postpone it and have it done later? Well, depending on your project priorities and your project objectives, you might want to go with one schedule versus the other, the other. Let’s think about the benefits of an as soon as possible schedule versus a late as possible schedule. What is it that we care about? Are we constrained by cost or by time?
And let’s think about how those two dimensions interact with our schedule. If we schedule activities as soon as possible we are incurring earlier costs and using our resources immediately. We are however, on in terms of time, giving ourselves some slack. We’re starting tasks as soon as possible even though we know that we have some slack in our schedule. And so, an this, as soon as possible schedule has benefits on the time dimension, but it does have downsides on our cost. We need to invest cost now in order to gain slack and buffer in terms of our timing.
And so if we’re constrained by time, and we’re planning a project in which the objectives are determined by the time and we’re going to compromise on our costs an as soon as possible schedule might be better. On the flip side, if we are constrained by costs, and we are working with a limited budget and we know that maybe ca, time is something that we can compromise on. We’re better off pushing our tasks as late as possible. As late as possible schedule delays the commitment of cost, delays the commitment of resources until a time that we know we must use it. Costs further down in the future are cheaper. However it eats, it eats up all the slack.
Postponing the tasks mean that we leave ourself with very little slack towards the end of our project and if we need extra time, we will not have it. And so if our priority is cost, you’re better off scheduling as late as possible.

In this video, Professor Yael Grushka-Cockayne explains how scheduling noncritical tasks is important in project planning. She poses the questions:

When do we schedule those noncritical tasks activities?
When do we think that we would like to perform the work?

During this video, you’ll work through the startup project example as several of the activities are non-critical and have some slack associated with them. As you watch the video, think about these questions posed above and how you would answer them in relation to your own project/s.

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Fundamentals of Project Planning and Management

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