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About this lesson
To link tasks together, the best approach is to insert the predecessor column into the Gantt chart entry table, then link tasks from the top of the project to the bottom.
Lesson versions
Multiple versions of this lesson are available, choose the appropriate version for you:
2013, 2019/365.
Exercise files
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Add Predecessors to each Task246 KB Add Predecessors to each Task
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Quick reference
Add Predecessors to each Task
To link tasks together, the best approach is to insert the predecessor column into the Gantt chart entry table, then link tasks from the top of the project to the bottom.
Your objective is to link all tasks in your project to define the critical path for your project. To verify all tasks have linkages, insert the successor column and verify there are no missing entries.
Further Discussion
By default, Microsoft Project uses a finish to start relationship for tasks. A good example of a finish to start relationship is you have to open the garage (finish) before you can back the car out (start).
There are times when you want a different relationship. Microsoft Project has many types but one of the more popular is start to start. A good example of a start-to-start relationship is you finish chopping the food (finish) and you can turn on the oven with one hand (start) and turn on the stove with the other hand (start).
Steps
When linking tasks with a predecessor relationship:
- Start at the top of the project and work your way down to the bottom.
- If multiple tasks can start at the same time, use the SS suffix at the end of the link, for example 8SS.
- Insert the successor column to identify tasks that do not have linkages.
- 00:05 Just as we’ve asked our team to estimate the tasks in our project and
- 00:09 the duration in our project.
- 00:11 We also need to ask them to tell us how all these tasks link together.
- 00:16 Now as you can see in the Gantt chart graphical view,
- 00:19 all these tasks right now start at the same exact time.
- 00:23 What we wanna do is have these be pushed out
- 00:26 based on a Predecessor relationship for the tasks.
- 00:30 Now I mentioned before that Microsoft Project uses constraints
- 00:33 in order to schedule tasks.
- 00:35 Well, there is actually a feature in Project called constraints, as well.
- 00:40 So for example, if I want this task to start on 11/2/2015,
- 00:45 I can go ahead and type that.
- 00:47 And what's happened is Microsoft Project created this thing called the constraint.
- 00:52 You can see that in the indicator column over here on the left side of the screen.
- 00:56 It says, This task has a Start No Earlier Than constraint.
- 01:01 Changing this date here is essentially the equivalent
- 01:06 of just trying to manage your project in Excel.
- 01:08 Where you're just typing dates and trying to make sure that things line up.
- 01:12 We do not want to use that, so
- 01:14 I'm going to do a Ctrl+Z or undo and remove that constraint date.
- 01:20 We want Project to calculate to the dates for us based on the Predecessor column.
- 01:27 Linking tasks is fairly straightforward.
- 01:30 All we really need to do is use the Predecessor column over here.
- 01:34 And we start linking the tasks.
- 01:36 Now, task number 1 is actually the start of the project, so
- 01:40 we don't need to link that one.
- 01:42 We do wanna link task number 2 to task number 1.
- 01:47 Why is that?
- 01:48 Because when we create this architectural design,
- 01:50 we're really not doing that until we know we have the land.
- 01:53 I'm not going to pay engineers to do that work,
- 01:56 until I actually have the land acquired.
- 01:58 So I'll go ahead and type 1.
- 02:01 And then, these progressively go down in a kind of waterfall fashion
- 02:06 where we're linking all of the tasks.
- 02:08 And you can see this on the Gantt chart.
- 02:11 You can see now that tasks are being moved out
- 02:14 based on the linkage to the tasks and the duration that the tasks have.
- 02:21 Now there's times when you don't just want to link tasks one after the other.
- 02:25 For example, if I come here to Install cabling, I linked that.
- 02:30 But there's no reason for
- 02:33 why we can't install cabling and plumbing at the same time.
- 02:37 So I'll type 8ss.
- 02:40 And what that's done is it's created a predecessor
- 02:44 relationship to install cabling and SS means start to start.
- 02:49 So if you take a look here on the Gantt chart,
- 02:51 basically these two tasks are going to happen at the same time.
- 02:56 Now if task line 7 changes, the duration changes.
- 03:00 I'll go ahead and just do this real quick, change it from 15 days to 20 days.
- 03:04 Watch what happens over on the Gantt chart.
- 03:07 The tasks move out but they're still happening at the same time.
- 03:11 I'm gonna do undo that change.
- 03:13 So task 7 is still is at 15 days.
- 03:17 Now I'm gonna go ahead and finish linking these tasks.
- 03:20 I know that Install HVAC can also happen after 7 as well.
- 03:30 And I'm going to finish typing the predecessor relationships for
- 03:33 the rest of the project.
- 03:39 At this point, we've essentially estimated how long the project is going to take.
- 03:45 However, there are some problems.
- 03:47 But before we review those, I wanted to just point out a few things.
- 03:51 Not all our tasks happened in a perfect sequence.
- 03:55 For example, this Hire interior designer.
- 03:58 Well, we can be looking for
- 03:59 that interior designer while work is being done on the house.
- 04:03 Probably makes sense after that Install house frame task is done
- 04:07 to find theirselves the interior designer.
- 04:10 So you can see on the Gantt chart how that lines up differently than the other tasks
- 04:14 surrounding it.
- 04:17 You might wanna move it Hire interior designer up, but it kind
- 04:20 of makes sense to have that interior designer with other tasks around it.
- 04:24 So we'll leave that task where it belongs.
- 04:28 Now, we are trying to create a critical path.
- 04:31 And this critical path is defining the list of
- 04:35 tasks that perform the longest sequence from beginning to end of the project.
- 04:40 We can't do that if all of our tasks aren't properly linked.
- 04:44 Now there's a few ways to decide whether all these tasks are linked.
- 04:48 One way, is to quickly look at the Gantt chart.
- 04:50 As you can see, this task doesn't seem to be attached to anything.
- 04:55 There's another way I can do that.
- 04:57 If I right-click on the Start column and
- 05:00 choose Insert Column, I can start typing the word successors.
- 05:05 And what you can see, is that there is a Successors column.
- 05:08 And if I press the Enter key on my keyboard,
- 05:12 what's happening is Microsoft Project automatically filled out this field for
- 05:16 us, as we were entering the predecessors.
- 05:19 And the one of the easiest ways to find missing tasks that
- 05:24 are unlinked is to come through here and look down the predecessors.
- 05:29 And then look back up the successors and you can see there's blank lines.
- 05:34 Now there's a way I personally like to link these tasks up.
- 05:39 And that's to use the network diagram.
- 05:43 I will cover linking these tasks together with a network diagram in the next lesson.
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