Develop Schedule

00:01 Hello and welcome.

00:03 This module covers the develop schedule process of the PMBOK guide. You'll see that it's rated high for difficulty memorization and exam importance.

00:17 There will definitely be questions in the exam on this topic, so pay particular attention.

00:23 You will be expected to complete a network diagram or be presented with a completed network diagram and asked questions about it.

00:34 It's rated high for difficulty because a lot of these concepts you may never have used before in your day to day job because a lot of them are what actually goes on behind the scenes of project management, scheduling software and in terms of memorization.

00:50 It's rated very high as well because of all the new concepts we have to introduce you to.

00:56 There may also be hidden within project management software and done automatically so the developer schedule process.

01:05 Is the sixth of six planning processes and the project time management knowledge area.

01:14 There is a single monitoring and controlling process in this knowledge area as well. And that's control schedule, but the developed schedule process is the culmination of all of the previous planning processes and the work that they've done.

01:31 We started off with a development of our schedule management plan, and we used that to guide all the rest of our planning work.

01:41 We defined our activities and produced an activity list and activity attributes. We sequenced our activities and produced an activity on node diagram showing predecessor and successor relationships and the dependencies between activities.

01:57 We then estimated the activity resources.

02:00 And with that information, we estimated individual activity durations. Now we're going to bring all of this information together to produce our project schedule.

02:14 The developed schedule process helps us understand the following domain task monitoring and controlling task for which says develop the project schedule based on the approved project deliverables and milestones, scope and resource management plans in order to manage timely completion of the project.

02:36 Now, the single domain task actually covers all of the time management planning processes, so it's pretty important for the exam that you pay attention to this one.

02:50 The key themes of the developed schedule process are, as I've already mentioned, we're going to bring together all of the outputs from the other time management planning processes to produce an agreed upon project schedule.

03:08 Once we have that.

03:10 Not only can we determine individual activity durations, but we'll be able to determine the entire project duration or parts of a project duration.

03:20 And calculate the critical path.

03:24 Using the network diagram, and we're going to show you how to do all of that. So pay particular attention to this module.

03:35 There are quite a number of inputs, most of them are outputs from the previous time management.

03:43 Knowledge area processes, but see if you can spot within these inputs outputs from other knowledge areas such as risk or cost or human resources.

03:55 So the first input that we would go looking for would be our schedule management plan because of course, the planning document provides guidance on how we do the work in the project, and that includes the planning work.

04:08 And as I've said, the develop schedule process is the culmination of all our planning work. But that doesn't mean it's the end of our planning work.

04:17 Don't forget that project management is always subject to iterations and progressive elaboration.

04:24 So we may initially start with a fairly loose project schedule.

04:28 Then, as we know more information about the project, our schedule becomes more defined.

04:33 There may also be changes that we encounter in our product project, which define or define changes to our project schedule.

04:42 The Schedule Management Plan will guide us on all of these activities.

04:45 So that's why we go looking for the schedule management plan.

04:49 It's one of our primary inputs.

04:51 We may also want the activity list and activity attributes both outputs from the defined activities process.

04:59 One of the earlier time management knowledge area processes.

05:04 We may also want our project schedule network diagrams.

05:09 That's an output from the sequence activities process.

05:13 We may want our activity resource requirements, so we know what resources are available to complete the work.

05:20 That's an output from the estimate activity resources process.

05:26 The resource calendars.

05:28 Direction output from some of the processes and the human resource management knowledge area, and they define the constraints upon resource availability.

05:37 So if it's people, it could be the resource calendars determining and defining the regular work week public holidays vacation time if the resource calendar is for machinery.

05:51 It may define when machinery is available to you and when it's not.

05:56 And this is particularly important if you're working in a weak matrix or functional form of organization where this constant negotiation and renegotiation for resources on your project.

06:09 We also want our activity duration estimates, which are an output from estimate activity durations.

06:16 One of the previous time management knowledge area processes.

06:21 We may want our project scope statement so we can double check that we've captured the entire project scope and of course, the scope statement is an output from the defined scope process out of the scope management knowledge area.

06:36 We may also want our risk register, which is an output from several of the risk management planning processes because the risk register is going to identify uncertainty about our project schedule and we need to build into our project schedule.

06:54 That uncertainty and account for it and also communicated.

07:00 We might also want projects, staff assignments, which is an output from some of the human resource management processes.

07:08 These are specific assignments for project staff on a particular part of the project and the roles they'll take and the work they're expected to do.

07:19 We may want our resource breakdown structure just so we can double check we've accounted for all of the resources that we need.

07:27 We may also want to take into respect enterprise, environmental factors and organizational process assets as appropriate for the development of our projects schedule. So once we have all of those inputs, we can then choose which of the following tools and techniques are most appropriate to use in order to develop our approved project schedule, which of course, is the goal of this process.

07:56 The first tool and technique that we may choose to use is schedule network analysis, and this is where we're going to use our network diagrams and we're going to complete a forward pass and calculate the project duration. And then we're going to complete a backward pass and calculate slack or float in each of the activities.

08:18 And then using the critical path method, take that information from our schedule network analysis and determine which of the many paths through our project is in fact, the critical path or paths.

08:32 Keep in mind for the exam, they can be more than one critical path through a project. However, many critical paths there are, they will always be the same duration and there will be no slack or float on the critical path.

08:48 Now, just a word on slack and float.

08:53 We know that the PMBOK guide is made up of what is generally considered good practice most of the time and most projects, and during the preparation of the PMBOK guide, a whole lot of useful project management information was gathered now for the purposes of making a concise body of knowledge.

09:12 A lot of that information was not included in the Pembroke guide.

09:17 A lot of it was put to one side, but the PMBOK guide clearly recognizes the value of all of it, but it's chosen to simply include.

09:27 Just those bits that the majority thought were more important.

09:31 What's interesting is one of the other things that the PMBOK guide does is attempt to give a single terminology because as we know, the profession of project management often uses multiple words to mean the same things.

09:46 And the PMBOK guide offers a single terminology or lexicon for the profession, except when it comes to the word slack and float. It's one of only.

10:00 Two times in the hole of the PMBOK guide were two words are used to mean exactly the same thing.

10:07 So feel free to use the word slack and float interchangeably, and that applies to free float and free slack.

10:15 Total float and total slack as well.

10:19 Of course, free float or free slack is the amount of float or slack and activity heads in it before it affects the next activity in the path. Total float, or total slack, is the amount of float or slack and activity heads in it before it affects the total project duration.

10:41 Another method we could use is the one developed by Eli Goldratt, and that's critical chain method, where we insert non-working time buffers into particular parts of our network diagram when we know we have uncertainty in our durations.

10:59 And we want a no surprises approach.

11:02 So we insert non-working buffer time into our network diagram and we can use that buffer up like a bank account.

11:11 There are several different ways to handle unused buffer.

11:15 But for the purposes of the exam, if you see a question referring to buffer.

11:22 You know that it's referring to critical chain method.

11:26 We may also wish to use resource optimization techniques, techniques such as resource leveling to get the most efficient allocation of resources.

11:36 However, a commitment to resource optimization can have impacts upon our project duration and we need to take that into account.

11:45 We'll have a look at another example shortly.

11:48 Other tools and techniques we may choose to use modeling techniques, particularly those using software using what if? Scenario analysis or Monte Carlo analysis.

12:02 So if in the exam, you see a reference to a supercomputer or a computer being used using linear regression or mathematical models to figure out different permutations of your project schedule, you're using modeling techniques and most likely what if scenario analysis or Monte Carlo analysis? We may also choose to use leads and lags as appropriate.

12:28 Now, if you recall from estimate activity durations, we use leads and lags as well as a tool.

12:36 There we were, applying leads and lags.

12:39 Here we are, adjusting leads and lags once again to put together our project schedule.

12:47 We may also choose to use some schedule compression techniques.

12:52 Now this occurs when we present our project schedule to stakeholders and they tell us, do it faster.

13:01 We may wish to investigate the use of either crashing or fast tracking as a way to do the project or parts of the project faster. We'll cover this again shortly.

13:14 But remember, the two most popular forms of schedule compression technique are crashing, which involves allocating more resources to an activity to do things faster and therefore generally it costs money.

13:29 The other technique is fast tracking, where we would optimally like to do activities in sequence.

13:37 But because their discretionary dependencies, we choose to do them overlapping and take on a bit more risk.

13:43 So I have a question in the exam implies spending money to speed up the project schedule that's crashing.

13:52 Or alternatively, if it asks you which technique to use and you have no more money available to you.

13:57 You can't use crashing and you would have to use fast tracking the final tool and technique that we may find useful as a scheduling tool.

14:07 Usually this is in the form of software.

14:10 And there are many, many, many fine forms of project management scheduling software out there on the marketplace.

14:18 I do recommend becoming very proficient in them.

14:21 And as I said at the beginning of this module, a lot of what we're about to cover is what actually goes on behind the scenes of the project management software.

14:31 So for the exam, you need to know all of this because there will be questions on it and your day to day life.

14:37 You may never need to use these things again, but you'll have a greater understanding of how you're scheduling tools are working.

14:46 So let's take a closer look at some of those tools and techniques.

14:51 The first being resource optimization techniques using a resource histogram. Now the graph in front of you.

14:59 That's a histogram and that shows our project schedule and the resources that we need in each time period.

15:08 So as we can see here, there's a lot of work being done early on in the year in January.

15:13 But if you have a look at April, there's very little work being done at all.

15:17 But we've got our project duration.

15:20 And how long we expect our project to take.

15:23 But overall, it's not a very efficient allocation of resources.

15:27 And also, we may find out that we're subject to a maximum number of resources. And this case, the dotted red line indicates the maximum numbers of hours per week we have for senior designers.

15:40 And that is one hundred and seventy five.

15:43 But there are clearly times in January where, according to our first pass at our project schedule, we need more than one hundred seventy five hours.

15:52 Obviously, if we had budget, we could bring in consultants or contractors to fill that gap. What we may choose to do is instead level the resources to get a more efficient allocation and not incur these costs because as well as there being an oversubscription of resources in January, take a look at April.

16:14 If those staff are on salaries, they're sitting around doing nothing for April. So during the development of your project schedule, you may look at greater efficiencies of resource optimization, and you may look at the consequences of moving some of that work in January.

16:31 Later on, in order to get below the maximum.

16:37 But that decision may impact upon the total project duration and may make it longer in the same way that moving some of that work to the down period in April.

16:48 So you don't have staff sitting around doing nothing may also extend the project duration.

16:56 Your decisions about resource leveling will come down to the primary constraints on your project as your project primarily constrained by resources, by time or cost that will dictate the extent of resource leveling that you undertake. Now, most resource leveling is done by project management software. I certainly would never encourage you to sit down with a piece of graph paper and try and do it yourself.

17:22 But be very careful when using project management software to do resource leveling, because unless you've input individual resource calendars for each individual resource in their software, choosing the automatic option can lead to some interesting results.

17:40 Modeling techniques, we can use these to give us different permutations of different scenario possibilities, and we may want to try and figure out which is our most likely outcome of a particular project schedule.

17:54 And this case, we're going to need a computer.

17:58 And we're going to use that computer to run through many simulations with different probabilities and different outcomes and give us likely outcomes for our schedule for a project.

18:09 Now for the exam, you just need to know that modeling techniques involve a computer linear regression and if so.

18:20 They are generally going to be what-if scenario analysis or Monte-Carlo analysis.

18:27 Just as an aside, Monte Carlo analysis got its name because it was used during the development of the Manhattan Project in World War Two and one of the uncles of one of those developers like to gamble at the casinos and Monte Carlo. Critical chain methodology, remember, this module is going to focus mainly on critical path methodology.

18:54 So in the exam, make sure you read the question carefully Is it talking about critical path methodology or critical chain methodology? Critical chain methodology was developed by Eli Goldratt, and what it does is it adds a schedule buffer between activities.

19:13 Now this buffer is based on transparent information.

19:17 It's based on historical information and knowing uncertainty.

19:22 It's not a case of simply padding of estimates.

19:26 Remember, for the exam, padding of estimates is considered unethical.

19:31 Now, padding is simply making up a number with no justification for either cost or time estimates.

19:38 Here, though, these buffers are based on expert opinion, historical information and a lot of other factors.

19:47 And the primary focus of putting these buffers in is to make sure that no activity exceeds its float.

19:54 So it means that you've identified some uncertainty, in particular activities or chains of activities.

20:00 Based on historical information, perhaps, and we've decided to put a buffer in there of three days or five days or seven days.

20:08 And it means that should the activity use none of its buffer, it will finish before that buffer starts.

20:14 But if that uncertainty eventuates, it can use some of that buffer up and you still don't affect the end project duration.

20:24 Now, different organizations have different rules and policies about what happens to unused buffer, whether the project duration is brought forward or the buffer can be then used for other parts of the critical chain for the purposes of the exam. You need to know critical chain means buffers.

20:43 So if you see a question referring to schedule buffers or Eli Goldratt, it is referring to the critical chain method.

20:53 The outputs from the developed schedule process include our schedule baseline. Are we going have a very close look at this in a moment with a large example? The schedule baseline is, of course, one of three baselines in the profession of project management.

21:10 The other two being our scope baseline and remember the scope baseline as our scope statement, plus our work breakdown structure, plus our work breakdown structure dictionary.

21:21 We also have our cost base line or budget.

21:25 Sometimes is also a quality baseline.

21:28 But we use our baselines to measure project performance and we compare what's actually going on to the baseline.

21:36 And if we find a difference between what's actually going on and the baseline, remember we act on it.

21:42 We always make sure that our baselines and what's actually going on are equal.

21:47 We may choose to change what we are actually doing or change the baseline whatever we choose to change.

21:54 We use our approved change control process.

21:57 We produce the project schedule.

22:00 We produce individual schedule data about different aspects of it.

22:06 We've reduced our project calendars, which tell us when our project will be occurring and we know it won't be occurring.

22:13 We also may choose to give updates to our Project Management Plan and all of its subsidiary plans, documents and baselines as a result of our first and subsequent attempts at putting together our project schedule.

22:27 Remember, our first go at putting together a project schedule could have huge implications for project cost or quality or stakeholder expectation management.

22:37 So as a result of the iterations we do preparing our project schedule, we may wish to update other parts of our project management plan.

22:47 We may also wish to update significant project documents, particularly lessons learned and also our project management methodology.

22:58 Here's one way that's typically used to represent a project schedule. The Gantt-Chart.

23:06 You notice Gantt-Chart has always spelt with a capital, G.

23:11 It's a surname of Henry L.

23:13 Gantt-Chart, who was a mechanical engineer in the early part of the 20th century, who's first credited with using this particular form of chart to show relationships between activities, and it is the most popular form of showing a project schedule.

23:29 I'm sure that you've prepared a Gantt-Chart in your time using project management software. A milestone Chat is particularly useful as well for showing significant parts of our project schedule the milestones we need to meet remember a milestone has no duration, zero duration and as an aside, it's always represented by that diamond shape that's an international standard for representing the milestone.

24:01 Another great thing about the milestone Chat is it's a very effective form of communication for senior managers.

24:09 Sometimes is a question in the exam, which says something like you've been called into a meeting with senior managers who want to know about your project schedule.

24:19 What is the best form of information you can take them? Well, because senior managers are busy and they want succinct information.

24:27 You don't take in your whole project schedule, you've taken your milestone chart. Show them the high level information.

24:38 As I've already mentioned in terms of schedule, compression techniques or speeding up the schedule, there are two main techniques you have available to you.

24:47 Crashing is where you add more resources to the activity and therefore it generally costs money.

24:54 These resources are generally in the form of approving over time or bringing in external consultants or hiring extra machinery from a higher company.

25:04 So adding those extra resources in order to do the work faster generally costs money.

25:10 So remember that in the exam, look for that clue.

25:13 And the question does the schedule compression technique involve more money? Then it's probably crashing.

25:20 And if you don't have any more money, you can't use crashing as a preferred technique to speed up the schedule.

25:28 The other schedule compression techniques that you'll be asked about include fast tracking. And this is generally where you would have preferred to do activities and sequence activity A then activity B, but in order to make things faster, you start activity B prior to the end of activity A.

25:49 Obviously, it relies on a discretionary dependency between the two activities, and you're taking on board an extra bit of risk as well.

25:59 And you can't have the same resources allocated to activities A and B, they generally work best when there's different resources allocated to them to keep those to schedule compression techniques in mind for the exam crashing and fast tracking. Now we're going to take a closer look at the critical path method, and this is going to involve completing a network diagram. So pay particular attention to the next part in this module because you will be asked questions in the exam about the critical path method.

26:32 You will be expected to either complete network diagram, comment on an already completed network diagram or make some changes to an existing network diagram.

26:42 So the critical path method is a way to figure out how long a project is going to take, but also how long an activity can be delayed before delaying the entire project.

26:56 And of all the potential paths through our project, which one or multiple are our critical path now? Any critical path in our project means that if an activity on that path is delayed, our total project duration will be extended.

27:13 Hence, why we call it the critical path.

27:17 We focus on that.

27:18 That is where we pay most attention to.

27:22 Of course, during a project, our initially identified critical path can change if there's very big delays on activities that aren't on the critical path. The critical path can change, so watch out for that as well.

27:38 Now we're going to take you through an example of putting together a network diagram, using an activity on node diagram.

27:47 I'm going to use a node that looks like this.

27:50 Each of the nodes has this information in it.

27:54 In the top left hand corner is going to be the early start, which is the earliest an activity can start in.

28:02 The top right hand corner of the node is going to be the early finish.

28:06 And that's the earliest this activity can finish.

28:10 And the bottom left hand corner.

28:12 We're going to have the late start, which is the latest this activity can start.

28:18 The bottom right hand corner is going to have the late finish, which is the latest.

28:25 This activity can finish in the top line in the middle.

28:29 We're going to indicate the duration of the activity.

28:33 In the middle, we're going to put the activity ID number or description.

28:38 And the bottom line in the middle, we're going to indicate the slack or float and that activity. So let's take you through an example.

28:47 This is the information that we're going to use and turn this into a network diagram. You may want to write this down and practice putting together your own network diagram.

28:58 So we've got activities a, b, c, d, e, f, g and H.

29:05 We've got our duration for each of them.

29:08 Activity A has three days duration activity, g four days duration and so on.

29:15 And we've also indicated the predecessors for each of our activities.

29:20 So Activity D, for example, has a duration of two days and it has activities B and C as predecessors.

29:29 Now for this example, we are assuming a finish to start relationship between all of our activities, which makes it nice and easy for us.

29:38 But what chart in the exam? Sometimes they start to start or finish to finish relationships. There may even be finished to start with a lead or lag applied.

29:51 So you need to practice your network diagram with each of those scenarios in it.

29:56 So let's take the information in this table and put together our network diagram will then complete a forward pass to figure out our total project duration and then we'll complete a backward pass to figure out our critical path.

30:11 So the first thing that we must do is put together our network diagram using that information about predecessors and successors.

30:20 Here is the network diagram for that information.

30:23 You'll see that Activity A is our first activity and it has three days duration. A successor to Activity A is Activity B with five days duration.

30:35 Also, Activity C with four days duration.

30:40 Activity D has two predecessors activities B and C, and so on.

30:48 And we've indicated.

30:50 What the durations are for each activities and at the end of this first step.

30:55 What we have is a network diagram using the precedence diagramming method, specifically the activity on node diagram.

31:04 But we don't have our project schedule yet, do we? There's no project duration and there's no critical path.

31:11 These are the next steps we're going to complete.

31:15 So the next thing we do is we calculate a forward pass. And this is where we move from left to right.

31:25 And as we move through the network diagram, we calculate the early start and the early finish of each of the nodes.

31:34 Now the way we do this is we start with the early start and we add that.

31:40 Well, add to that the the activity duration.

31:44 Now I can see you looking at activity, a going well, hang on a moment.

31:48 One plus three should equal four.

31:52 Let's take a closer look at that, though.

31:54 So Activity A begins at the beginning of day one.

32:00 It's three days long.

32:02 So at the beginning of day one, then day two, then it ends at the end of day three. So we're going to say that Activity A is three days long. It begins the earliest it can start is the beginning of day one, and the earliest it can finish is actually the end of day three.

32:20 There are some other methods of calculating this which would have it start at zero and that, but we won't use that for the purpose of the exam.

32:28 You will use this numbering technique.

32:30 Just be aware there are some textbooks out there which use a slightly different numbering technique. This is the numbering technique that's in the PMBOK guide.

32:37 So activity a.

32:40 The earliest it can start is the beginning of day one.

32:43 It has three days duration, so day one day to day three.

32:48 It ends at the end of day three.

32:52 Now, take a look at Activity B, it's an immediate predecessor to activity A.. So the earliest it can start is in fact the beginning of day four. Remember activity a end at the end of day three? Activity B begins at the beginning of day for activity B has five days duration.

33:15 So beginning of day four day, five day, six day seven end of day eight, that's five days.

33:23 So the earliest activity B can finish is day eight activities. C also has Activity A as a predecessor, and it two can start at the beginning of day four.

33:38 It has four days duration, so it starts at the beginning of day for day four day five day six.

33:45 The end of day seven is the earliest activity C can finish.

33:51 So let's continue with our forward pass and look at activity D now, of course, Activity D has two predecessors Activity B and Activity C.

34:05 So the earliest activity D can start.

34:10 Is after the lighter of its two predecessors.

34:14 Now, of course, activity see ends at the end of day seven, but Activity B doesn't end till the end of day eight.

34:22 So Activity D, which is a successor to both of those, can't start.

34:29 Until the beginning of day nine.

34:31 So the early start for activity day is the beginning of day nine.

34:35 It has two days duration.

34:37 So that's the beginning of day nine end of day 10 for its early finish activity. A has an early start at the beginning of day eight, which is immediately after the early finish of activity.

34:49 See on day seven.

34:51 Activity E has six days duration beginning of day 8, 9, 10, 11, 12.

34:58 End of day 13 as the earliest activity can finish.

35:03 We go on to calculate activity, if once again it has two predecessors.

35:10 So we look at each of the predecessors Activity D and Activity A, and we look at each of the early finishers activity.

35:20 D has an early finish of day 10 activity A has an early finish of day 13, so it has to be the higher or later of the two predecessors that affect activity if in this case, activity A.

35:36 and day 13.

35:38 So activity if can start at the beginning of day 14.

35:42 It has five days duration.

35:44 So days 14, 15, 16, 17 end of day 18, that becomes the early finish for activity.

35:52 If Activity G only his one predecessor and that's activity A.

35:59 So it can start immediately after the early finish of activity a day 13 so it can start at the beginning of day 14.

36:07 So the early start for Activity G is day 14.

36:11 Four days duration takes us to an early finish of day 17, and now we come to the last activity in the network diagram activity H.

36:22 Again, it has two predecessors activity if and activity G, the higher of the two predecessors, early finish is activity if with 18.

36:35 So activity H, the early start is the beginning of day 19.

36:41 It has seven days duration, so that means it ends at the end of day 25 and that's a forward pass.

36:50 Now we don't have a project schedule completely yet, but what we do have is a project duration and that's twenty five days.

37:00 Forward path left to right.

37:03 Calculating early start and early finish the entire way and with a forward pass, we end up with our project duration.

37:11 Now let's take a look at a backward pass.

37:14 This is where we move from right to left.

37:17 Calculating late start and late finish.

37:20 Pay particular attention to the backward pass as it may take you several attempts to understand it. What we're going to do in this instance is calculate the late finish and the late start now for Activity H, which is the last activity in our network diagram.

37:38 The late start and the late finish are the same as the early start and the early finish.

37:45 You can see an activity h.

37:47 We've calculated the amount of slack or float in that task that's calculated by subtracting the early start from the late start or the early finish from the late finish.

37:59 It will give you the same answer.

38:01 So in this case, using the early start and the late start 19 minus 19, we can see we've got zero slack or float in activity h. So let's work backwards now from right to left.

38:15 The next one we want to work out is the late start for activity if and the late start for activity G.

38:22 This time we look to the successor activities and we look to the late start of our successor activities. In this case, the late start of activity is eight day 19. Therefore, the late finish for both activity if an activity G is day 18.

38:44 Now we can simply subtract the duration from those late finishes in order to get our late starts.

38:52 One of the tips I have is that the difference between your early finish and your late finish will be the same as the difference between your early start and your late start.

39:05 So for activity F our late finish is day 18.

39:11 A late start as day 14.

39:14 We can see that our slack or float is zero for activity if for activity G, on the other hand, our late finish is day 18. Which makes our late start day 15.

39:29 Now, if we subtract one of our earlies either our early start or early finish from the equivalent late start or late finish.

39:37 So 15 minus 14, we get slack or float of one day, which means that activity g the earliest it can start as day 14, the latest it can start without affecting the project.

39:49 Duration is, in fact, day 15.

39:52 It has one day slack or float.

39:54 Now let's continue with our backward pass and calculate the late finish and late start for activity D and the late finish and the late start for activity e activity D is the simpler to calculate.

40:07 So let's start with it.

40:09 It has a single successor activity activity.

40:12 If so, the late finish for activity D is immediately before the late start for activity.

40:19 If so, in this case, the late finish is day 13.

40:24 With a two day duration.

40:25 The late start becomes day 12.

40:29 Now, if we subtract our early start from our late start, 12 minus nine, we get three day slack or float in activity day.

40:38 We like that activity.

40:40 It's got three day slack or float in it activity a.

40:44 On the other hand, has two successor activities, so we need to look at them both. And look at the smaller of the two late stats activity. If has a late start of day 14 activity G has a late start of day 15.

41:01 So the one that we want is activity if and it's late start of day 14.

41:06 So activity a it's late finish becomes day 13 immediately before the day 14.

41:13 Late start of activity if.

41:16 With six days duration, the the late start becomes day eight, and there's no difference at all between our early start and our late start, so we have zero days slack or float and activity a.

41:31 Working backwards again.

41:33 Activities see has a single successor activity.

41:38 So the late finish for activity C is day seven, which is immediately before day eight, the late start for Activity A with four days duration.

41:49 The late start becomes day four.

41:52 Once again, there's no difference between our early start and our late start.

41:56 So the slack or float is zero days.

42:00 Activity B, its late finish is immediately before the successor activity activity D, so that's a late finish of day 11 with a duration of five days, it has a late start of day seven.

42:17 The difference between our late start of seven and our early start of four is three days, so Activity B has three days slack or float in it and finally coming all the way back to activity A..

42:31 So remember, we look at both of its successor activities, activity B and Activity C, and we look for the smaller of the two late stats, which in this case is activity.

42:43 See with a late start of four days, which means that activities a late finish is the end of day three.

42:52 It's got a three day duration.

42:54 Therefore, it's late start is the beginning of day one.

42:57 Once again, there's no difference at all between our early start and our late start, so the total float is zero.

43:04 Now we've completed a forward pass to find out our project duration and a backward pass to work out our critical path.

43:11 And this is how we work out our critical past.

43:14 We take a look at all of those activities with zero slack or float in them.

43:18 So that's activity a.

43:22 See? A.

43:27 If. And H.

43:31 And that is our critical path through this network diagram, A, C, E, F and H.

43:39 Of course, with a bigger network diagram with a lot more activities, you would find multiple critical paths.

43:45 But remember, they're always the same duration and there's no slack or float on any of the activities in there.

43:54 So if any of the activities a f or h are delayed, our total project duration will increase beyond 25 days.

44:02 And that's why we pay attention to the critical path.

44:06 Now, keep in mind throughout your project if Activity D, for example, was delayed by more than three days.

44:14 Then it would probably become on the critical path.

44:17 So the critical path can shift during a project as well.

44:23 So in summary, the developed schedule process takes together all of the schedule information we've produced as a result of all of those other schedule management or time management planning processes.

44:38 The defined activities, the sequence activities, the estimate, activity resources, the estimate, activity durations and also takes information from other knowledge areas in the PMBOK guide, such as risk management, human resources puts them all together to produce a project schedule.

44:56 And with that, we can identify a project duration and also the critical path.

45:03 As I've already said in this module, please pay particular attention to the development of the critical path and completing your own forward pass and backward paths. There are always questions in the exam which require you to be able to do that in summary.

45:19 Thank you very much for listening.

45:21 This has been a module on the develop schedule process in the PMBOK guide.