Add Lag and Review the Critical Path

Quick reference

• 00:04 You have done a lot of work so far to create a Microsoft Project schedule.
• 00:09 However, one of the things that we have not done yet,
• 00:11 is to really look at how we can optimize the plan.
• 00:15 This is something you always want to go back and do with your team.
• 00:19 So for example, after your team has suggested the tasks, the durations,
• 00:23 the linkages with the predecessor successors,
• 00:26 and we've taken a look at the resource assignments.
• 00:30 We want to step back and say, did we miss anything?
• 00:33 Can we make the project come in a little bit earlier?
• 00:37 Or are there things that we forgot that's going to push the project out?
• 00:42 So I'm gonna talk a little bit about using the critical path and
• 00:45 making some adjustments to your schedule so
• 00:48 that you have a better picture as to when the project will be complete.
• 00:53 When we make changes to our project,
• 00:56 we want to keep an eye on any task that's critical.
• 01:00 Now, remember that critical tasks mean that if you change by even one day,
• 01:05 you'll change the entire duration of the project.
• 01:09 Let me show you what that means.
• 01:10 First, make sure you're in a Gantt chart view.
• 01:13 Then click the Gantt Chart Tools contextual format tab.
• 01:18 In the bar style section, you'll find a Critical Tasks check box.
• 01:23 Just go ahead and select that.
• 01:25 So when you select this, you'll see that the bars in the Gantt chart turn red.
• 01:31 I can also insert a column to the right of task name, so if I right click
• 01:35 task name and choose insert column, I'll type critical and press Enter.
• 01:41 Now you can see there are certain tasks that are critical and
• 01:44 certain tasks that are not.
• 01:46 Watch what happens when I change acquire land from 30 days to 31 days.
• 01:51 Watch the full duration of the project.
• 01:54 Right now it's at 207 days.
• 01:55 So I'll change acquire land to 31, and now the duration of the project is 208.
• 02:00 I'll change this to 29, and you can see the duration of the project is 206.
• 02:06 I'll set this back to 30 days.
• 02:11 So that's how we can see the impact of changing critical path tasks.
• 02:17 So far I've spent a lot of time talking about critical path tests and
• 02:21 how important they are, but what if a task is not in the critical path?
• 02:24 Let's just scroll down a little bit here, and
• 02:27 let's take a look at these blue tasks over here.
• 02:31 I'm gonna zoom in a little bit, so I'll move things around and zoom in.
• 02:36 That's a little bit too much.
• 02:40 There we go.
• 02:41 So, we have these tasks here that clearly have some time in between.
• 02:45 So if I click the Format tab again, the Gantt Chart Tools Format tab, and
• 02:50 click this Slack check box, you'll see how the Gantt
• 02:53 chart is showing this little line underneath some of these tasks.
• 02:58 Well this line is representing how much time
• 03:01 you have before the task falls into the critical path.
• 03:05 I can also insert a column for this.
• 03:07 So if I right-click on Task Name, and choose Insert Column,
• 03:11 I can type free slack and press Enter.
• 03:17 Now what I can do is take a look at this task.
• 03:20 Hire interior designer.
• 03:22 It says there is 38 days of free slack which means 38 days plus
• 03:27 5 days is what would make this task fall into the critical path.
• 03:35 So if I type 43 and press Enter, you can see it goes into the critical path.
• 03:41 If I type 42 or anything less, it will not.
• 03:45 So, if I need to spend more time finding and
• 03:48 hiring an interior designer, then I actually have time to do that.
• 03:53 I’ll press Undo a few times to get this back.
• 03:55 So that’s just a quick little overview of how we look at critical tasks and slack.
• 04:02 The next thing we’re going to do is make a few minor adjustments to our tasks.
• 04:07 Now as I talk to my team,
• 04:09 I find out that there’s two tasks that we need to make some adjustments to.
• 04:13 The first is task number 11, Install house frame.
• 04:16 My team member rightly points out that we can't be walking around in wet cement.
• 04:20 We have to install the house frame after it's dried.
• 04:23 So I'm gonna double click on Install house frame, and go to predecessors, and
• 04:27 create a lag of five days, and click Okay.
• 04:31 What this does is it pushes out the task five days for us.
• 04:36 I could have inserted another task that said wait for foundation to dry, but
• 04:41 that would just be some new task that I need to manage.
• 04:44 Or I could have hand entered a date, but
• 04:46 remember we do not want to ever hand enter a start date.
• 04:50 So this works out really well for us.
• 04:51 Now it says ten, link to task ten, finish to start plus five days.
• 04:57 We'll add a note, and this note will help us remember why we did this.
• 05:02 Added five days positive lag to Wait for
• 05:08 foundation to dry.
• 05:13 We can do that one more time, but in the opposite direction.
• 05:17 So here's task 25, Add furniture.
• 05:20 One of my team member points out that we don't have to wait exactly until
• 05:24 this Build out kitchen task is done.
• 05:26 So I double-click, choose Predecessors, and
• 05:30 set the lag to -6 days for this Build out of the kitchen.
• 05:37 And what we've done is we've pulled the task in
• 05:40 to actually finish a little bit earlier.
• 05:44 In total we've brought the entire project down by one day.
• 05:48 It was at 207 days, now it's at 206.
• 05:51 So we push one task out five days, but we brought another task in six days

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