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About this lesson
Utilize the network diagram to see how all the tasks link together and create a critical path.
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2013, 2019/365.
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Quick reference
Create the Critical Path
After you manually link tasks with the predecessor column, you should display the successor column. If any tasks do not have a link in the predecessor or successor columns, you should investigate why this is. Remember, you do not need to link the first task that starts the project, but all other tasks should have a link. When all tasks have predecessor and successor links, you will be able to create a critical path.
The project summary task (task zero) or any other summary task (which shows as bold in the Gantt chart view), should never be linked.
Further Discussion
One helpful tool to help you link tasks is the network diagram. By using the network diagram, you can visually see how all the tasks link together. You can drag-and-drop one task to another to form new links.
As mentioned in previous lessons, some tasks start at the beginning of the project. Any of these tasks can start without a predecessor link. The last task in a project will never have a successor because there are no more tasks to complete after it.
Steps
To use the network diagram, follow these steps:
- Click the tasks tab.
- Click the Gant chart picklist.
- Select the Network diagram option.
- Locate any task(s) that do not have a link and drag-and-drop a link from one task to another.
Important: Never link summary tasks. Summary tasks are in the shape of a parallelogram (crooked rectangle).
Login to download- 00:04 We have taken our first pass at linking all of the tasks together using
- 00:08 the predecessor column.
- 00:10 In the previous lesson,
- 00:12 I pointed out that the successor column fills in for us automatically.
- 00:16 Now, sometimes you'll see these blank lines here on the successor column.
- 00:21 And that's bad because that means some tasks aren't fully linked.
- 00:27 And you can see that here with this hire interior designer task.
- 00:32 If we look over here, we can see that it is actually linking back to
- 00:36 installing the house frame, however, no other task is linking to it.
- 00:42 If we don't link all of the tasks together,
- 00:45 then we do not get the critical path.
- 00:48 What's important about the critical path is that if one task moves, just even
- 00:53 one day, all of the other tasks could move out, pushing the project out one day.
- 00:59 So all critical tasks need to be identified and accounted for.
- 01:03 And we can only do that by linking all of the tasks together.
- 01:08 If it is very clear to us which tasks to link together, we can just go through and
- 01:14 type that linkage immediately right here in the predecessor or successor column.
- 01:20 However, sometimes you want to identify these tasks in a number of different ways.
- 01:25 The way I like to do it is to use the network diagram.
- 01:29 And we access a network diagram by clicking the Task tab,
- 01:33 clicking the pick list for Gantt Chart, and choosing Network Diagram.
- 01:39 Now, in the network diagram, I'm going to scroll all the way to the left and
- 01:44 I'm going to zoom all the way out.
- 01:46 I'm using the zoom control on the bottom right hand side of the screen.
- 01:50 So what we can see here is the start of our project, which is the My New House,
- 01:55 that's task line zero.
- 01:57 And remember, we do not need to link this task.
- 02:00 Now, task line zero, and any other summary task that we create, is represented by
- 02:06 a parallelogram, which is essentially just sort of this shifted rectangle.
- 02:11 We don't need to link those ever.
- 02:13 We shouldn't actually link those together.
- 02:16 So we're using the network diagram is to easily identify tasks that don't
- 02:20 have a linkage in the project.
- 02:22 And actually there's a few of them.
- 02:24 So if we come over here and mouse over this task, it says hire interior designer.
- 02:30 Well, we need to link that task to something else.
- 02:33 Chances are, it gets linked to something close by.
- 02:37 So let's take a look at some of the other tasks around it.
- 02:40 Here's install roofing, here's install siding,
- 02:45 here's install drywall, and here's paint walls.
- 02:49 Well, I think the interior designer is going to be painting those walls.
- 02:54 So what we're going to do is say that this task and
- 02:59 this task are linked together.
- 03:02 We have another task up here that's not linked, that's install plumbing.
- 03:06 If I come over here, we have install siding.
- 03:09 So we can install siding after install plumbing is done.
- 03:13 So again, we'll drag and drop the task there.
- 03:18 We have one more task that's not linked, this is install furnishings.
- 03:23 Now, here's an interesting one.
- 03:25 These furnishings are probably the same job as the interior designer.
- 03:30 So we can actually link one task to multiple tasks.
- 03:34 So here's the install interior designer, I'm going to also link that task to it.
- 03:40 And finally,
- 03:41 I want to make sure that this is linked to another task throughout the critical path.
- 03:47 And by the way, all these red items,
- 03:50 these are all marked as critical path because they're red.
- 03:55 So I'm going to look at this, and this is install furnishings.
- 03:59 Here's paint walls, here's build out kitchen, here's add furniture.
- 04:06 So I'll go ahead and associate the furnishings with the furniture.
- 04:14 Now, I'll go ahead back to the Gantt chart by clicking the Task tab and
- 04:18 clicking Gantt Chart.
- 04:22 Now we've linked all of our tasks together.
- 04:25 Notice that some tasks are linked with a comma.
- 04:28 You can actually link multiple tasks to one single task.
- 04:33 So now install furnishings is linked to tasks 13 and 15.
- 04:40 Let's take a closer look at this install furnishings task with 13 and 15.
- 04:46 Notice on the Gantt chart, we have arrows going up and down.
- 04:49 We have this because this install furnishings is not located in the right
- 04:54 place.
- 04:55 The interior designer is going to do that, and
- 04:57 they can't do that until after we've hired them.
- 04:59 So let's take line 14, click on the row, use your mouse to drag it under 15.
- 05:05 And now you can see the arrows are all flowing in our waterfall method.
- 05:09 So we've used the network diagram now to link the tasks.
- 05:13 And we've reviewed our Gantt chart to make sure we don't have tasks pointing up and
- 05:19 down in it.
- 05:19 And we now have a full critical path for our project.
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