Create the Critical Path

Quick reference

• 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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