Understanding Work Breakdown Structures and Task Sequencing in Project Management

The goal of the work breakdown structure is to list all of our tasks, but it is not to sequence them in the overall project. So we do have to think about sequencing. The reason we don't think about sequencing right away is because we kind of think about logically grouping all of the things to make sure we don't forget anything, but then we need to take all of those things and put them into a sequence, which for one specific deliverable, you might have different parts of that being done all throughout the project, which to kind of look at it all, when things are intermixed with each other, that might be hard to think that way in the initial planning, but once you have all that list of tasks, then you can go about sequencing them and creating the overall schedule.

So when we think about sequencing or ordering our tasks, we can use something called a network diagram to arrange and order all of those activities into an appropriate sequence. We think about the dependency of do we need to do one thing after another? For example, if we're going to paint a room, we need to first prep it, then we paint it, and then we can do the trimming on the room. So the network diagram defines the sequence of how we're going to do activities.

We think about the dependent relationships. Some things have to be done one thing after the other. Some can be done at the same time.

So we're going to think about that logical sequence of one thing after the other. Now when we think about the sequencing, we need to diagram it somehow. So generally speaking, we're going to have a box with the activity in there.

It's normally a verb because it's an action. It's something that we're doing. There is an activity number, which is just a unique identifier for that.

The number does not convey the order of things per se. By that I mean every different activity is going to have a different number. So this is step three and step four, which in this case is one after the other.

We need to wash the car before we dry the car, as indicated by the arrow. But if we saw the steps prior to this, we'd have step one and step two, which depending on their relationship, maybe we can do steps one and two at the same time, and then after they're done, wash the car. So I'd have to see the diagram to know, is it two steps that happen one after the other prior to washing, or are we doing two things at the same time and then washing the car? So the number is just to convey a unique activity number.

So I can say, hey, let's talk about task four in this diagram. So think about the different ways that we can sequence activities. One of them is a serial or kind of linear sequence, one after the other.

So especially if you don't have a lot of resources, let's say it's just you painting, you don't have any friends, or they're all out of town for the weekend or the week. But let's say it's just you, or you can only afford to hire one painter. When you have limited resources, you would have to do one thing after the other.

So if we're going to do three rooms, we're going to prep, paint, and trim the first room. We're going to prep, paint, and trim the second room. We're going to prep, paint, and trim the third room.

This is one way that we could do this. And let's just, for easy math, assume that each step is going to take one day. This would take nine days.

Okay, so that's one way you could do this. Now you could also, let's say, prep room one, prep room two, prep room three, do all the prep first, then paint room one, paint room two, paint room three, do all the painting, and then finally do all the trim of room one, of room two, and room three. Of course, that would require some place to put all the stuff from those rooms, or you'd have to cover all those rooms.

You know, if you do the first room, you could take all the things from it and stick it into room two while you're working on the first room, and then once you're done with the first room, move everything back from room two, put it back into room one, and move on to room two. So you have to think of those kind of things of what order you want to do these things in. Now, sometimes you can also do things concurrently.

So if you're painting three rooms, if you have enough resources, if you have enough people, let's say you're hiring a company, or it's you and you got two friends that can help you out, then one of you, or one of the people, can take room one, another at the same time can do room two, and another person at the same time can do room three as well. Now this will require more resources, so you need more people, and let's say you are paying for those people. This is going to cost you more, right, instead of you just doing it all yourself.

Now it took, let's say, nine days. This could be done in as little as three days here, but you need more people. Same amount of hours worked by people, three people times three days each, that's nine days, so it's still the same number of work days, you're just doing them at the same time.

Now likely this will be more expensive, at least a little bit more expensive, because you need three sets of supplies. You need three paint brushes, three rollers, three trays, if there's ladders, maybe three ladders at the same time. You're going to need more resources to support these people, even if they're free labor where you're getting some friends to come over, so it'll at least cost you a little bit more, and if you're hiring a company, if you were to hire an individual person that is just working themselves, probably that person would work at a cheaper hourly rate than, let's say, a company that has to have overhead of staff, where they're paying staff, whether they're working or not, to be able to have three on-staff people to come paint the house, so you'll probably pay more for this type of work, and generally speaking, to get it done faster, you would have to pay more, usually speaking, but if you need something done faster, you could get this project done in as little as three days, if you're willing to spend more, or you could get it done as slow as nine days, if you're just doing it by yourself, or just have one person doing it.

Now, you could also do something where it's in-between, do a laddering kind of technique, where, let's say, you on the first day, you start prepping the first room by yourself. The second day, you go on to prepping the second room while you bring in one helper, or pay one person to come in to paint the room, and then you move on for the third day to prepping, the painter moves on, and you bring in one more person, so only on this middle day is it three people. All the other days are either two or one, so two of those days, you get to work by yourself, you don't have to have somebody else helping, and at most on one day, you need two people.

This is somewhere in-between those other two, where it's not as fast as three days, this is five days, it's not as long as the nine days, so it's somewhere in-between. You can do any of these plans depending on how fast you need to get things done, what your available resources are, right, what if you don't have those people to call on, what if you can't afford to hire a company that has these people, so you have to look at those constraints, things that you have to work within, and also another thing to think about, things like laddering is, let's say your initial plan was to do something like this, you were going to save some money and do this all yourself, but partway through, you get the call that over the weekend, some family or friends are going to come stay at your place, and you're like, wow, I need to get this done faster, so the plan changes midway through. You could switch to, let's say, a laddering technique, where you bring in one or two other people to get it done faster, so sometimes when you are executing your plan, something needs to change, so in that case, you might have planned for it to take longer, and maybe you're falling behind schedule, or just for some other reason, something changes, and you want to switch things up, so keeping these in mind, that even if this is not what you initially choose, that you can always use this later during the execution phase.

Right now, we're in the planning phase, and we're creating our initial sequence of what we plan to do, it's our baseline that we're going to use, then during execution, we'll see, are we going to keep to that, or are we going to need to make changes if necessary. Think about what factors do we think about when sequencing our activities, what factors kind of play into that. Go ahead and pause the video, think about it, and then come back.

So some of the factors we think about when sequencing our activity are the number of resources that we have. I might want to do something faster, but I might not have enough resources to do it faster. We think about the relationships of tasks.

Can they be done concurrently? Does it have to be done one after the other? We think about things like constraints. How much time do we have? What's the budget? What's the scope? We think about those things, because if I don't have enough time, then I'm going to need to figure out, as long as I have the budget, how to do something faster. All of these things play into how we decide what our initial sequence is.

Other things to think about when sequencing our activities are when we think about an individual task. What activity or task must be finished before this activity can be started? Because you want to make sure that if you're going to do something, that all the prep work or things that need to be in place to do that are done. For example, you want to dig the hole for the foundation.

You need to make sure you have a permit. So if you forgot to get the permit, people show up to do their work that day and they can't work. So what needs to be done before we do this thing? So you're thinking backwards.

You also think concurrently. So you think backwards. You think concurrently.

What else can be done at the same time so that we can speed things up? And you think going forwards. What activities happen next? So what do I have to do now so that I can do the next following activity? So in other words, I think backwards. I think forwards.

And I think at the same time, kind of in all three directions. So we're creating our project schedule based on this network diagram of sequencing. And it's showing the order and relationships of these activities.

One thing to keep in mind is those activities should be thought of in terms of kind of measuring progress. So let's say if you have a three-year project and you're going to be reviewing things on a monthly basis, if you have things that are going across all of those months, it's hard to review where you're at in those things. We look at things that we are accomplishing.

So ideally, you would break these activities down into smaller bite-sized chunks. So instead of just having one giant thing, like build a building, right? There's a lot more that goes into building a building than just building that building, right? So you want to break these things down, right? It is a work breakdown structure. You want to break things down into kind of bite-sized little pieces that you can sequence, that you can also measure that we're making progress through those things.

So that when you look at things, let's say on a monthly basis, you can look at how many activities you've accomplished in those. So take those longer tasks and break them down into smaller tasks so that you can better measure those individual tasks. Let's take a look at another example here of sequencing.

So in this case, they are creating a printed questionnaire that they're going to mail out to some consumers. That's the overall project here. And we're just looking at a portion of this project.

So in the beginning, Susan is going to be potential target consumers to send this questionnaire to. And she is going to then develop a draft questionnaire based on the type of people that she is going to be targeting. And because it's going to be a mailed questionnaire, they do not want to waste money on printing and postage if it's not very good, if there's confusion about the questionnaire.

So she's going to do a small little pilot test with a few people that have agreed to give feedback, and we can review their comments and finalize the questionnaire. Now, once that has been finalized, then the team can start to put all of this stuff together. Steve can be preparing the mailing labels and printing the questionnaire all at the same time.

Andy can be developing the data analysis software that is going to accept all of these questionnaires. We're going to feed it in and it's going to analyze the data. And Susan wants to be testing the software as well.

So she's going to create some test data, some kind of fake questionnaires to give Andy so that once he's done, she can give him those to run through and do some tests all before they get back the final things. And there will be more things after that, but some things can be done at the same time and other things have to be done one after the other. And the thing that is different about a network diagram compared to something like a Gantt chart, a Gantt chart is showing the sequence of things, but you have to look in two places.

You have to look over at the name of the task. And then over here, you have to look at the length of duration of how long these tasks are. So the Gantt chart is good at showing the duration of things, but you have to look in two different places.

So if you're focusing purely on order and sequencing and those sorts of things, the network diagram is a bit more focused on that. It does not convey visually the length of these tasks, even though we can add duration, we don't make them bigger or smaller depending on the length of the task like a Gantt chart does. So they both do very similar things and you can do sequencing technically with either one, but the network diagram is more focused on sequencing things.

These are examples of things that you could do in Microsoft Project, where there are different ways to view your project. In the network diagram, we can add activity durations, which we would normally do at the bottom right corner. So the left corner is the unique activity number and the bottom right is the duration.

So whether this is hours or days or whatever unit of measurements you want, generally keep them all the same. So you can know in this case, let's say this is five days. When we think about estimating duration here, because we're in the planning phase here, we want to think about how long it takes to do the activity, plus if there's any waiting time.

We want to think about all the things that take up time to do something. So let's say there was the interviewing of the client. You want to think about all the things for the interview.

It's not just the interview time. Let's say that was a few hours that you were going to interview. There's the travel time to meet the client.

There might be waiting time. So if you're leaving early in case there's traffic, you might have to be waiting there. There's the actual time of the interview.

And if it's several hours, there might be short breaks or lunch. And if you need actually three hours, but you're going to take a half an hour break, you would need to schedule three and a half hours of time. Then there's the travel time back to the office.

You know, so something that might take three hours of an interview might be an all day event with all the things to and from with travel and all the things that are involved. Now, when it comes to estimating those durations, you should be consulting with the people who are the subject matter experts. We call them SMEs for short subject matter experts.

Does that necessarily mean they're an expert? Not necessarily. It means that they are the knowledgeable person that we are talking to, and they may be really good at this. They may not be really good at this, but we still show them respect and call them subject matter experts.

This would be the person either assigned to the task or the kind of person who would be assigned to the task. You don't necessarily know in the planning phase who exactly will be doing this. You might talk to somebody in that same type of role to say how long would it take you? How long would it take someone in your role to do this? Instead of just saying this should take this long, we want to find out from them how long do they think it will take.

Now, people can be bad at estimating. You know, they are guessing, they are estimating based on their knowledge how long something will take, and that can be wrong. It's hard to see into the future and know exactly how long something's going to take.

This is a at past projects. If you've done these kind of things before, look at how long it's taken you in the past. If you have estimators in your company, I know my brother is an estimator at a construction firm, and there's a whole department of estimators that estimate, in his case, things like costs of how much it's going to cost to do a project, but he has to factor in time and all that stuff into how much something's going to cost.

There are whole estimation departments at certain companies. That depends on your particular company if you can rely on them or not. We also want to think about when we're coming up with this duration of how long would it take someone in that role to do that? Not necessarily a specific person, like what if that person is not available? So let's say Sue is really fast at doing something.

What if Sue is not available? What if we get stuck with the slowest person? So you want to think about an approximate time of how long somebody in that position would take, unless you know exactly, oh yeah, this person is going to be available for this project. And the reason I mention that is because, for example, in the scenario of, let's say you're bidding on a government job, that might be you need to get accepted, the bid needs to be reviewed, that could take time. We all know governments are fast, right? No, I'm just kidding.

Governments can take a while. So that might be, you might be doing that in one to two years from now. So who knows if the person you're consulting with today is even going to be at the company in one to two years.

There might be somebody else in that role. So you might talk to a couple people about how long they think it'll take. And one thing that I like to add to that is also how confident are you in that estimation? Because sometimes when I estimate something, I'm really pretty sure at how long something will take.

Other times, I'm not sure. So if you just ask how long do you think this will take, and you don't know their confidence level, you don't really know whether you should potentially consider adding extra time just in case they're wrong. So I like to find out how long do they think it'll take and how confident are they in that estimate, just as an idea of something to think about.

So as an example here, if you have these different tasks and you're filling in task numbers and durations of time, task one, two, three, four, five, in terms of times, we put in the two days, the three days, the one day, the three days, the two days. And in this particular example, this project, think about how long would this project take? Total days. Don't look over here.

Look over here. How many total days would this take? Pause the video. Okay.

So this task C is being done at the same time as D. So it does not add to the total time. Two plus three is five. Another three plus two is five.

So five plus five is ten. This will take ten total days. And by the way, we just found what's called the critical path.

The critical path is this bottom path, and it is the sequence of tasks that must be done in order with no delay to be able to do this in ten days. Because task C can be done on the first, second, or third of these three days. So that task can float around in the schedule a little bit.

It has some slack, as we'll learn later.