Skill Level Intermediate
- [Bonnie] Hi, Bonnie Biafore here. In Project, total slack is the time a task can move without affecting the project finish date. If total slack is negative, that tells you how much you need to shorten the schedule to deliver on time. In this project tip, I'll show you how to display negative slack so it's easier to figure out how to shorten the schedule. In this project, I'm gonna scroll down to the bottom of my task list.
I have a task, number 90, event day. If you look in the indicators column, there's an icon there of a calendar, but it has a yellow triangle with an exclamation point. If you position your pointer over that, the warning tells you that the task starts on a date that's different than its must start on date constraint. So that's a problem. We're gonna need to somehow get some time back in the schedule to get this to occur when it should.
Now, before we go any further, if you don't see this indicator, let me show you the options that you need to change. So let's go to the file tab, and then on the left side, click options. In the project options dialog box, click the schedule category, and go to the scheduling options for this project section. There's a checkbox, tasks will always honor their constraint dates. You want to make sure it's turned off.
When it's turned off, that means the tasks won't honor their constraint dates, but you get this handy indicator that tells you that there's something wrong. And that's what you want. So let's go ahead and click okay to close that dialog box. The next thing I'm gonna do is I'm going to apply the schedule table to this view so I can see total slack values. I'm gonna go to the view tab, and then in the data section, click tables and choose schedule.
The last column on the right is total slack, and you can see that event day has negative 5.63 days of total slack. So that means to get this to occur when it should, I have to shorten the schedule by this many days. Before we go any further, I also want to see the task bars over in the time scale, so let's go to the task tab on the ribbon, and then at the very right end in the editing section, click scroll to task, so I can see my task bars.
Now what we're gonna do is we're gonna use the task path feature. That shows the predecessors to a task, and so we can identify tasks that maybe we can shorten to get this schedule back on track. But the one thing you'll notice is when you look at the bars over in the time scale, there's a milestone, event setup complete. When I select that it's task ID 88. That's a milestone that is the one task that drives event day, so what we really want to do is we want to move this milestone back in time.
So I'm gonna select that milestone, and then I'm gonna use the task path feature to find predecessors to this task so I can find a way to shorten it. Go to the format tab, and then in the bar style section, click task path. I'm gonna start by choosing predecessors, but then I'm gonna click task path again, and choose driving predecessors.
Driving predecessors mean the tasks that directly affect when this milestone occurs. Then when I scroll up a little bit, you can see there are a couple of milestones here that have turned orange. Both of those are driving predecessors to our event setup complete. But what I'm gonna do is I'm gonna look at task 78, event preparation complete. That has a task here, and actually to see the task names the way, in full, I'm going to point at the right side of the task name column and drag to the right so I can see my full task names.
Well, let's look at this task 76, train sales staff. That is controlling when event preparation complete occurs. And it runs for more than three weeks. Down in the task form view, you can see that the duration is 16 days. Well, let's say that you contact the marketing content developer and say, "Hey, is there any way you can shorten this training to two weeks?" And if she says, "Yeah, we'll have to work and see how everybody's schedules are, but yeah, we can do that." So you can go down to the task form and change duration to 10 days, and then click okay.
Now let's scroll down and look at our event day. We've gotten it back to the start date of April 10th. In addition, I want to see if my missed date constraint indicator has gone away. So I'm gonna go up to the top left corner of the table and right click this box, which is called the select all cell. That shows me a shortcut menu with different tables in it.
So I'm gonna select summary, so I can get my indicators column back. Well now I have to scroll back down to the bottom, but when I do that, sure enough, the indicator has changed. It's a calendar to say yes, there is a date constraint on the event day task. But there's no yellow triangle, so I know that event day is starting when it should. Of course, not every schedule is that easy to change.
But now you've seen how to use the total slack field and the task path feature to find ways to get your schedule back on track.