3.2 Constructing a Schedule

Welcome back, and let’s take a look at how we actually construct a schedule. What we’re going to do first is move all the detailed tasks onto to the project schedule. Where do they come from? They come from the WBS. We’re going to add task durations. So, specific task durations, we’re gonna put those on the schedule. And we’re going to arrange the tasks into sequences and simultaneous relationships that we think work the best. Then we’re going to either add the start of the project, or the completion of the project. At the start of the project, we’ll schedule the project from the beginning on through. If we start at the completion of the project, we schedule backwards to see when we should start the project. Hopefully, we don’t find and should have start at three months before today. We’re also going then to add the early and late start and finishes to each task. And you can pull whatever other information you want to at some other point after you get the structure for the schedule put together. And we get the times put in there. Let’s look at an example what this is actually all about. We’re gonna start with our go to work WBS. On here, we have some times. We have converted these times on our WBS to durations. It may have started as work, which we will talk about in the next module. What we’re going to schedule with durations, so these have all been changed to durations. It takes ten minutes to get out of bed. We’re kinda slow these days, we hit the snooze alarm a couple of times, we don’t just jump up right out of bed like we used to. We have to think about the day’s tasks. What’s going on today? That’s gonna take us five minutes to do, so. These are all the durations for these tasks. We put our schedule together, we’re going to find that the headings go away on a network diagram. Don’t put the headings for tasks. We’re not going to get out of bed, review the day’s tasks, and then go start the day. Get out of bed and review the day’s tasks are start of the day. So start the day isn’t going to be a task we put on our schedule. These are the tasks that go on the schedule. We also notice that the last heading out there, get into the car to drive to work. Well, that one doesn’t go away. Why? There are no subtasks underneath there. The WBS does not need, need to be broken down into the same level of detail across the entire WBS. So it might go two levels deep. Some might go nine levels deep. It doesn’t make any difference. Whatever you need to do on that part of the WBS is what you do. We’re gonna turn this into a go to work network diagram. So, we’re actually going to construct the schedule here. We’ll use our go to work WBS for a little mini project here. We’re going to start with an activity on node format. And it’s a, like we said, that’s often a good planning tool. If we choose, we can turn that into a Gantt chart. We’ll start with the network diagram first. Not all project managers use network diagrams and Gantt, Gantt charts. Most project managers use only one of these and most of the time project managers use Gantt charts. If we’re going to use a network diagram, again, which is a really good planning tool and especially a good tool to use with your team. This is the building block. We have a box here that has the activity, the duration for that activity, early start, late start, early finish, and late finish. Early start, the earliest time this task could ever possibly start in this project. The early finish, the earliest this could possibly ever finish if everything went exactly right. Late start, the latest we could ever start this project and still get this, this start this task and still get this project done on time. The late finish is the latest we could ever finish this task and still have the project come in on time. We need that information and then we can put together a schedule. We start to arrange our tasks, put them together in whatever order we think they go in. So we’re gonna get out of bed and the next thing we think we’re going to do is review the day’s tasks. We think also while we’re reviewing the day’s tasks, we can also shower. One of those males who could actually multitask, you can think and shower at the same time. Where do all of these tasks come from? They come right from the WBS that we had before. We just move them right from the WBS onto the schedule. What we’re doing is we’re, we’re just gonna tear the WBS to pieces and put it together in a different format now. A milestone. We noticed that one of the tasks on here, get in the car had zero duration. Milestones are zero duration tasks that designate some sort of a significant point in the project. So here, getting in the car, is a significant point in the project, so it shows up as a milestone, it’s also zero duration task. This is our entire schedule for getting out of the house. We’re getting, waking up in the morning and we’re in the car. We’re not at work yet, this is only part way. So, it’s just the beginning of our whole journey to get to work. Right now, we’re sitting in the drive way in the car, now we gotta get from there to the car to the office from that point. This is what the whole thing looks like when it’s all filled in. What does this show us? It shows us the relationship of the tasks. It shows us which, it shows us which tasks lead to which others. It also shows us where the critical path is. If we look at this, we look at the early start, late start, the early finish, late finish of each of these five tasks. The early start, earl, early start, late start is the same and the early finish, late finish is the same on each of these. Those are critical path tasks. For example, shower could start as early as minute ten, has to start at minute ten. Be done as early as a minute and 25, has to be done by a minute and 25. There’s no extra room in any of those tasks. It also shows us, as well as the critical path, where we have some float time in the project. So if we look at these three tasks across the bottom, these three tasks across the bottom all have an extra five minutes of float to share. They don’t each have five minutes of float. That whole group of tasks has five minutes of float. So the total float is five minutes for that group of tasks. If the first task uses up all five minutes, the other tasks don’t have any float left over. There’s no free float for them. Total float to five minutes across the five, the three tasks here. Total float, whatever’s left over after the preceding tasks have used up that float. Float time. Remember there’s the total float we looked at, and the free float. We can see both of those on our project schedule now. Look through here, how much free float is left over? This also can be displayed as a Gantt chart. Here’s the same project. This project. In this project, very same project, just different views. This is a good planning tool when we’re starting to put things together, putting all this together, seeing how all these tasks relate to each other, it’s a good way for a group of people to work together to put a project schedule together. This is a pretty good way now to take a look at the project during executing and how things are moving along. We can look at any specific date along here and see how we’re doing. So we started off with our go to work WBS, and we rolled it into our Gantt chart. When we looked at our WBS, it has the headings on here. And if we go into a Gantt chart, we can also put those headings on here. The headings typically do not go on a network diagram, but on a Gantt chart, you’re often gonna see those, and those are those big dark bars across a group of tasks, and they’re called summary tasks. That’s the heading, like start the day, clothing, food, those actually show up on a Gantt chart, typically. Here on our Gantt chart, we also see the critical path of the project and we see the float time. All of those red tasks are the critical path of the project, ending with a milestone put on the Gantt chart as a little diamond shape, little diamond shaped piece. And the float time across there shows up in blue. We are told that we wanna see it in different color. Gantt chart, what do we see on a Gantt chart? Early start, early finish, past duration. The connecting lines that we see on there. They’re exactly the same connecting lines that we’ve seen before, either a dependency line or a predecessor line. We’ll say this task is followed by another task. That task is dependent. If we say this task had something happen before then we talked about a predecessor line. Software. There’s a lot of good ones out there. Microsoft seems to be the main one, MS Project seems to be the main one that people use. There are other ones and there are a lot of clones of MS Project right now. We have baseline and we’ve seen some examples of both of those. That’s what we just were looking at. Baseline. Once we get our schedule laid out, we have a baseline for the project. You don’t change the baseline. The only way to change the baseline is if you go back and redefine the project. Baseline stays the same and now we use that to judge how we’re doing with the rest of the project as we move forward. Human resource constraints. We’re going to first lay out our, our, our schedule. We’re going to determine our critical path based on task relationships. And then we might find that because we can’t get some of the people we need on the specific dates we need them, that changes our schedule. And so now, when we’re finally done with the critical path, it’s built on task relationships and the availability of people that do the tasks at certain times. What we might find, is that when we lay our schedule out, we have a project that takes longer than the amount of time we have available. So this one, the earliest we can start this project and when it has to be done, is longer than the amount of time that we have. We have some options available to us. One is crashing the project. Crashing the project means that we shorten up the durations that we have on individual tasks. Fast tracking the project means we’re going to do things simultaneously, concurrently, in parallel, that we thought we had to do in sequence before. The problem with crashing the project, it can increase the costs on the project. The problem with fast tracking the project, it can increase the risks on the project. There’s one other way to do this which is reduce the scope of the project. And also a second way that these are not the preferred ways, these are the alternate ways. Reduce the scope of the project or reduce the quality. Just take some things out of the project or reduce the quality that we have for the project overall. So those are our ways to change our project if it doesn’t fit into the time frame allotted, crash the project, fast track the project, reduce the scope or as a last resort, reduce the quality.