Welcome back to our course on Project 2016.
In this section we’re going to look at the Critical Path in Project 2016.
In the preceding section we saved a baseline for our wedding project and now we’re going
to look at the Critical Path.
The reason that I want to look at the critical path now is because as we start to track progress
on a project it’s very often the case that things start to go wrong.
Things get delayed, they take longer than expected, perhaps cost increase.
And any one time you may need to get back to a situation where you are saving time,
you’re making up for slippage on a project.
And when you need to make up for slippage what you really need to know is which tasks
are really driving when this project is going to finish.
The set of tasks that determine when a project is going to finish is called the Critical
Path.
And the tasks within the critical path are usually referred to as the Critical Tasks.
So the first thing I’m going to do with the wedding project is to find out what our
critical tasks are.
Now in order to do that in Gantt Chart View if I go to the Format Tab in the Bar Styles
Group one of the options there, there’s a checkbox, Critical Tasks.
And if I check Critical Tasks it will show all critical tasks in red.
Note the Screen Tip description there.
A task is critical if it must be completed on schedule for the project to finish on schedule.
So if I check Critical Tasks you can see that the red tasks are the ones that are actually
determining when this project is going to be completed.
Now sometimes, and particularly with a project with a lot of tasks in it, it’s difficult
to see the critical tasks.
They may be spread out quite a bit as are these.
And there is a way of only showing the critical tasks.
And in order to do that we’re going to look at another important aspect of views.
So now I’m going to click on the View Tab and I’m going to apply a filter.
Now in this case the filter I’m going to apply, note the control there with the little
picture of the chemical filter there, is Critical Tasks.
So the filter is called Critical.
And now I only see the critical tasks in my project.
Now it’s quite often the case when you look at the critical path on a project that it
is a continuous critical path.
What I mean by that is that for every day of the project from the very beginning to
the very end there is at least one critical task happening.
In this particular project that is not the case.
There are I think three significant gaps.
And sometimes gaps are completely explicable.
They’re there for a good reason.
No problem with them at all.
Sometimes they can indicate that maybe there’s a problem with the way that you have your
project setup.
Let’s just take a quick look at a couple of the gaps here just to give you an idea
of how these things can occur.
I’m going to look first at the one towards the end.
So this is the one that occupies quite a bit of August and it’s the gap after Select
honeymoon destination and Book honeymoon which is a critical task and Wedding day which itself
of critical because it’s the end, it’s the last day of the project.
Now the reason there’s a gap there is because I setup that 21 day contingency.
So I said that Wedding day is going to be 21 days after the end of the preparation phase.
Now given the definition of what a critical task is, it’s one that’s happening and
can’t slip.
There are no tasks occurring in that period so none of them can be critical.
So that’s a perfectly legitimate gap in a critical path.
The gap in the middle is largely down to the effects of resource leveling.
And what can happen sometimes is that although we’ll know one particular task has to be
completed by a particular day you have a lot of work to do.
You can probably be reasonably flexible in the order in which you complete the tasks
subject to dependencies, constraints, etcetera.
But basically you just have a lot of work to do in the time and resource leveling will
sometimes cause gaps.
The first gap, that’s after Agree budget and approach and before Make reception venue
shortlist, there is actually a task active there which is Making of the guest list.
And there are dependencies on that although the dependencies on Making the guest list
are based on its start date not its end date which will sometimes stop a task from being
critical anyway.
But the gap here is largely down to a combination of leveling and task prioritization as well.
So in many ways this particular project schedule is quite unusual.
The critical path is quite unusual because of the number of gaps but there are reasons
for those gaps.
And you will tend to get gaps, for example, in projects where you have a lot of resource
issues and also where there isn’t a very definite sequence through the project.
You’ve got a lot of things to do over a period of time but the sequence isn’t as
well defined as it is say in the bathroom refit.
So what I’d like to do now is show you another way of looking at criticality of tasks.
And first of all I’m going to change the table that’s in use here.
I’m going to go back to the Entry Table and I’m going to insert an additional column
in here.
I’m going to insert column and what I’m going to insert is called Finish slack.
And what Finish slack shows me is the slack, the amount by which any task can be delayed,
its finish can be delayed without affecting the end of a project.
Now for critical tasks their finish slack is zero days.
And as you can see all of these red tasks have a finish slack of zero days.
In fact in Project 2016 you can change, if you like, this definition of critical and
say for example that any task with two days or less finish slack is regarded as critical.
We’re not going to look at this on this course.
For the moment we’re going to stick with the standard definition that a task is critical
if its finish slack is zero days.
That means that if it was even one day late it would affect the end date of the project.
Now let me remove that critical filter and let’s look at the finish slack on all tasks.
Now if you look at something like Select wedding dress that’s got 48 days of finish slack.
So that could be 48 days late, bear in mind various other tasks follow on after that.
But it could be 48 days late without affecting the finish date of the whole project.
And if you look down at all of the other tasks in the schedule you’ll see that all of the
noncritical tasks have in many case a significant amount of finish slack.
Something else that you might well find useful, again if I go to the Gantt Chart Tools Format
Tab, underneath the Critical Tasks checkbox in the Bar Styles Group there is a Slack checkbox.
And if you enable that for each task you will see a visual indicator of its slack.
Now of course for the critical tasks there is no slack.
But if you look down at other tasks you’ll see a line.
If you take, for example, this one, measurement and fittings, look at that line that goes
out to the right hand end, the black line.
It indicates the slack on that particular task.
The slack also shows on summary task.
So the various summary tasks within the preparation phase you can see how much slack there is
in each of those as well.
So that again gives you a good visual indicator of how much slack there is in individual tasks
within your schedule.
So in this section we’ve looked at the Critical Path and Critical Tasks and at Slack.
A couple of other things to mention.
If I go back to the Resource Tab and go into Leveling Options.
Again I mentioned this earlier on.
Level only within available slack.
If you click on Level only within available slack that does severely limit the amount
of leveling that Project is able to do but it does also mean that you don’t cause delay.
And secondly if you need to shorten the project, possibly to deal with a delay during the running
of the project, the place to start is with the Critical Path because it’s the Critical
Tasks on the Critical Path that basically determine when the project is going to finish.
So the critical tasks are the place to start.
That’s the end of this section.
In the next section I’m going to set you Exercise 06.
Please join me for that.